[ { "type": "text", "text": "Django ", "text_level": 1, "bbox": [ 149, 112, 294, 143 ], "page_idx": 0 }, { "type": "text", "text": "本身基于 MVC 模型（架构），即 Model（模型） $^ +$ View（视图） $^ +$ Controller（控制器）设计模式，MVC 模式使后续对程序的修改和扩展简化，并且使程序某一部分的重复利用成为可能。但在 Django 中更常被称为 MTV（Model-Template-View）。", "bbox": [ 144, 161, 848, 212 ], "page_idx": 0 }, { "type": "list", "sub_type": "text", "list_items": [ "模型（Model）：负责应用程序的数据和业务逻辑。通过将数据和逻辑从用户界面分离出来，使得模型可以独立于用户界面进行测试和修改。", "视图（View）：负责显示用户界面，但通常没有直接访问应用程序的数据。这使得可以更容易地更改应用程序的外观而不影响数据处理。", "控制器（Controller）：处理用户输入、更新模型和调整视图。通过将用户输入和应用程序逻辑分离，可以更容易地更改用户界面的交互方式而不影响数据和业务逻辑。" ], "bbox": [ 159, 217, 845, 347 ], "page_idx": 0 }, { "type": "text", "text": "Django 提供了全栈开发所需的工具，包括数据库ORM、模板引擎、路由系统、用户认证等，大幅减少重复代码。", "bbox": [ 144, 366, 815, 379 ], "page_idx": 0 }, { "type": "text", "text": "Django 的哲学:", "text_level": 1, "bbox": [ 146, 397, 245, 410 ], "page_idx": 0 }, { "type": "list", "sub_type": "text", "list_items": [ "DRY（Don't Repeat Yourself）: 避免重复代码，提倡复用（如模板继承、模型继承）。", "约定优于配置: 默认提供合理配置（如自动生成Admin 界面），减少决策成本。", "快速开发：Django 提供了大量内置功能，如认证、管理后台、表单处理等，让开发者专注于业务逻辑，而非底层实现。", "自动化管理后台：只需简单的模型定义，即可生成强大的后台管理界面，支持增删改查。", "ORM 数据库映射：Django 内置 ORM (Object-Relational Mapping)，可以让开发者使用 Python 类与数据库交互，无需编写 SQL。", "强大的 URL 路由：使用正则表达式灵活定义 URL，轻松实现页面路由。", "模板引擎：内置强大的模板系统，支持逻辑判断、循环处理，方便渲染 HTML 页面。", "国际化支持：Django 支持多语言国际化，非常适合全球化应用。", "高安全性：内置多种安全保护措施，如防止 SQL 注入、XSS 攻击、CSRF 攻击等。", " 丰富的社区与扩展：大量开源的第三方库，如 Django REST framework、Django CMS 等，快速扩展功能。" ], "bbox": [ 174, 428, 850, 757 ], "page_idx": 0 }, { "type": "image", "img_path": "images/f4487cc28d0ed6be5aa3b6d12a641d265ce457c6192d9a6a0c73c17c74dfe081.jpg", "image_caption": [], "image_footnote": [], "bbox": [ 149, 771, 426, 883 ], "page_idx": 0 }, { "type": "text", "text": "内置功能", "text_level": 1, "bbox": [ 147, 130, 273, 154 ], "page_idx": 1 }, { "type": "table", "img_path": "images/5d60b0537c37007c990ae2b61e846c3457cfbc1fa80f09239c115f6a3a8da393.jpg", "table_caption": [], "table_footnote": [], "table_body": "
功能说明
Admin后台自动生成管理界面，无需手动编写CRUD逻辑。
ORM用Python类操作数据库，无需写SQL。
表单处理内置表单验证，防止CSRF攻击。
用户认证提供登录、注册、权限管理（django.contrib.auth）。
路由系统URL映射灵活，支持正则表达式。
缓存机制支持Memcached、Redis等后端。
", "bbox": [ 147, 162, 998, 475 ], "page_idx": 1 }, { "type": "image", "img_path": "images/9e8b7b91d694be7a68319af4130f4b3e88f070e1faac0f9b9d52e5a8c0d292a6.jpg", "image_caption": [], "image_footnote": [], "bbox": [ 147, 506, 715, 709 ], "page_idx": 1 }, { "type": "text", "text": "MVC (Model-View-Controller) ", "text_level": 1, "bbox": [ 147, 730, 586, 755 ], "page_idx": 1 }, { "type": "list", "sub_type": "text", "list_items": [ "Model (模型)：处理与数据库的交互，定义数据的结构和业务逻辑。", "View (视图)：负责数据展示，生成用户看到的HTML 页面。", "Controller (控制器)：接收用户请求，调用Model 处理数据，并将结果传递给View 渲染页面。" ], "bbox": [ 174, 766, 761, 841 ], "page_idx": 1 }, { "type": "text", "text": "流程：", "text_level": 1, "bbox": [ 147, 859, 184, 871 ], "page_idx": 1 }, { "type": "text", "text": "1. 用户发送请求到 Controller。", "bbox": [ 176, 890, 371, 902 ], "page_idx": 1 }, { "type": "list", "sub_type": "text", "list_items": [ "2. Controller 处理逻辑，调用 Model 获取数据。", "3. Controller 将数据传递给 View。", "4. View 渲染并返回 HTML 页面给用户。" ], "bbox": [ 176, 93, 470, 168 ], "page_idx": 2 }, { "type": "text", "text": "MVT (Model-Template-View) —— Django 的实现方式", "text_level": 1, "bbox": [ 144, 191, 826, 253 ], "page_idx": 2 }, { "type": "text", "text": "Django 中采用了MVT 设计模式，类似于MVC，但有一些区别：", "bbox": [ 144, 263, 527, 278 ], "page_idx": 2 }, { "type": "list", "sub_type": "text", "list_items": [ "Model (模型)：与数据库交互，处理数据的创建、读取、更新、删除。", "Template (模板)：负责页面渲染，生成最终的HTML 内容。", "View (视图)：Django 的View 更偏向于控制器的角色，接收请求并决定使用哪个模板和数据。" ], "bbox": [ 174, 296, 757, 370 ], "page_idx": 2 }, { "type": "text", "text": "流程：", "bbox": [ 146, 388, 184, 401 ], "page_idx": 2 }, { "type": "text", "text": "用户访问 URL，请求被 Django 的 urls.py 映射到相应的 View。", "text_level": 1, "bbox": [ 144, 426, 789, 445 ], "page_idx": 2 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "url.py下 \nurlpatterns $=$ [url(r'^search-form/\\$,search.search_form)，#映射到search.py中search_form视图url(r'^search/\\$,search.search)， #映射到search.py中search视图url(r'^search-post/\\$,search2.search_post),#映射到search2.py中search_post视图]", "bbox": [ 206, 460, 747, 627 ], "page_idx": 2 }, { "type": "list", "sub_type": "text", "list_items": [ ". 当访问 /search-form/ 时，Django 调用 search.search_form 视图函数", "当提交表单到 /search/ 时，调用 search.search 视图函数" ], "bbox": [ 176, 645, 645, 688 ], "page_idx": 2 }, { "type": "text", "text": "View 处理业务逻辑，调用Model 获取数据。", "text_level": 1, "bbox": [ 144, 714, 589, 733 ], "page_idx": 2 }, { "type": "text", "text": "(1) 渲染搜索表单（但是这里无Model交互）", "bbox": [ 206, 747, 470, 760 ], "page_idx": 2 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "# search.py\ndef search_form(request):\n return render(request, 'search_form.html') # 直接渲染模板", "guess_lang": "python", "bbox": [ 206, 778, 576, 854 ], "page_idx": 2 }, { "type": "text", "text": "流程：", "bbox": [ 176, 871, 243, 883 ], "page_idx": 2 }, { "type": "text", "text": "View 只负责返回模板，未涉及Model 数据操作", "bbox": [ 205, 890, 489, 902 ], "page_idx": 2 }, { "type": "code", "sub_type": "algorithm", "code_caption": [ "(2) 处理搜索请求（带参数校验）" ], "code_body": "def search(request): request_encoding $=$ 'utf-8' if $\\mathrm{q}^{\\prime}$ in request.GET and request.GET['q']: #业务逻辑判断 message $=$ '你搜索的内容为:' $^+$ request.GET['q'] else: message $=$ '你提交了空表单' return HttpResponse(message)#直接返回响应（未用模板） ", "bbox": [ 206, 155, 591, 357 ], "page_idx": 3 }, { "type": "code", "sub_type": "algorithm", "code_caption": [ "（3）# 接收POST请求数据" ], "code_body": "def search_post(request): \nctx $= \\{\\}$ if request.POST: \nctx['rlt'] $=$ request.POST['q'] \nreturn render(request, \"post.html\", ctx) ", "bbox": [ 206, 406, 455, 545 ], "page_idx": 3 }, { "type": "text", "text": "View 将数据传递给 Template。", "text_level": 1, "bbox": [ 146, 599, 470, 620 ], "page_idx": 3 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "return render(request, 'search_form.html') ", "guess_lang": "lua", "bbox": [ 206, 663, 460, 676 ], "page_idx": 3 }, { "type": "text", "text": "在这个例子中，search_form 只是用来展示HTML 表单页面，没有动态数据传入。", "bbox": [ 206, 694, 687, 708 ], "page_idx": 3 }, { "type": "text", "text": "虽然这里没有传递变量，但你可以通过 render 的第三个参数传数据给模板：", "bbox": [ 206, 725, 653, 738 ], "page_idx": 3 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "return render(request, 'search_form.html', {'key': value}) ", "guess_lang": "lua", "bbox": [ 206, 756, 542, 769 ], "page_idx": 3 }, { "type": "text", "text": "第二个没有传输数据因为根本没有template", "bbox": [ 208, 789, 468, 803 ], "page_idx": 3 }, { "type": "text", "text": "第三个例子", "bbox": [ 208, 822, 278, 835 ], "page_idx": 3 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "return render(request, \"post.html\", ctx) ", "guess_lang": "lua", "bbox": [ 206, 854, 438, 866 ], "page_idx": 3 }, { "type": "list", "sub_type": "text", "list_items": [ "1. Template 渲染 HTML，最终返回给用户。", "模板文件: search_form.html" ], "bbox": [ 176, 95, 450, 137 ], "page_idx": 4 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": " ", "guess_lang": "txt", "bbox": [ 176, 250, 226, 261 ], "page_idx": 4 }, { "type": "text", "text": "Tip：HTML
action 属性", "text_level": 1, "bbox": [ 146, 291, 500, 311 ], "page_idx": 4 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": " ", "guess_lang": "twig", "bbox": [ 176, 351, 413, 363 ], "page_idx": 4 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": " ", "guess_lang": "twig", "bbox": [ 184, 384, 363, 395 ], "page_idx": 4 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": " ", "guess_lang": "txt", "bbox": [ 184, 414, 400, 426 ], "page_idx": 4 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "
", "guess_lang": "txt", "bbox": [ 176, 445, 226, 456 ], "page_idx": 4 }, { "type": "text", "text": "(1)
标签 ", "bbox": [ 176, 476, 278, 489 ], "page_idx": 4 }, { "type": "text", "text": "action=\"/search/\" ", "bbox": [ 176, 508, 322, 518 ], "page_idx": 4 }, { "type": "list", "sub_type": "text", "list_items": [ "o 表单提交的目标URL地址", "o /search/ 表示提交到当前网站的搜索端点（例如 https://example.com/search/）", "o 尾部斜杠/ 表示这是一个目录路径（符合RESTful风格）" ], "bbox": [ 236, 539, 744, 612 ], "page_idx": 4 }, { "type": "text", "text": ". method=\"get\"", "bbox": [ 176, 632, 300, 643 ], "page_idx": 4 }, { "type": "list", "sub_type": "text", "list_items": [ "o 使用 HTTP GET 方法提交数据", "o 表单数据会附加在URL后（如 /search/?q=关键词）", "o 适合不修改服务器状态的查询操作（如搜索）" ], "bbox": [ 236, 663, 576, 736 ], "page_idx": 4 }, { "type": "text", "text": "2. 实际工作流程", "text_level": 1, "bbox": [ 146, 755, 247, 766 ], "page_idx": 4 }, { "type": "text", "text": "1. 用户交互", "bbox": [ 176, 787, 265, 799 ], "page_idx": 4 }, { "type": "list", "sub_type": "text", "list_items": [ "o 在文本框中输入内容（如\"无人机\"）", "o 点击\"搜索\"按钮 " ], "bbox": [ 236, 816, 473, 860 ], "page_idx": 4 }, { "type": "text", "text": "2. 浏览器行为", "bbox": [ 176, 879, 278, 891 ], "page_idx": 4 }, { "type": "list", "sub_type": "text", "list_items": [ "o 自动组装 URL：/search/?q=无人机", "o 发起GET请求（HTTP头部示例）：" ], "bbox": [ 236, 93, 485, 137 ], "page_idx": 5 }, { "type": "text", "text": "GET /search/?q=无人机 HTTP/1.1", "bbox": [ 146, 156, 354, 168 ], "page_idx": 5 }, { "type": "text", "text": "Host: example.com ", "bbox": [ 146, 187, 265, 199 ], "page_idx": 5 }, { "type": "text", "text": "3. 服务器处理 ", "text_level": 1, "bbox": [ 176, 218, 278, 230 ], "page_idx": 5 }, { "type": "text", "text": "o Django路由将请求交给对应的View处理：", "bbox": [ 236, 249, 517, 261 ], "page_idx": 5 }, { "type": "text", "text": "# urls.py ", "bbox": [ 146, 281, 203, 293 ], "page_idx": 5 }, { "type": "text", "text": "path('search/', views.search) ", "bbox": [ 146, 311, 319, 323 ], "page_idx": 5 }, { "type": "text", "text": "# views.py ", "bbox": [ 146, 343, 215, 354 ], "page_idx": 5 }, { "type": "text", "text": "def search(request): ", "bbox": [ 146, 373, 270, 385 ], "page_idx": 5 }, { "type": "text", "text": "query $=$ request.GET.get('q') # 获取参数\"q\"的值 ", "bbox": [ 161, 405, 452, 417 ], "page_idx": 5 }, { "type": "text", "text": "return HttpResponse(f\"搜索内容：{query}\")", "bbox": [ 161, 436, 421, 449 ], "page_idx": 5 }, { "type": "text", "text": "渲染过程: ", "text_level": 1, "bbox": [ 147, 535, 248, 554 ], "page_idx": 5 }, { "type": "list", "sub_type": "text", "list_items": [ "1. search_form 视图调用 render(request, 'search_form.html')", "2. Django 模板引擎找到 templates/search_form.html", "3. 生成纯静态HTML 返回给用户" ], "bbox": [ 236, 569, 638, 642 ], "page_idx": 5 }, { "type": "text", "text": "第二个方式没有模板渲染，直接返回httpresponse响应。", "bbox": [ 146, 661, 482, 674 ], "page_idx": 5 }, { "type": "text", "text": "第三个例子", "bbox": [ 206, 694, 278, 707 ], "page_idx": 5 }, { "type": "text", "text": " ", "bbox": [ 206, 725, 480, 738 ], "page_idx": 5 }, { "type": "text", "text": "{% csrf_token %} ", "bbox": [ 221, 756, 329, 769 ], "page_idx": 5 }, { "type": "text", "text": " ", "bbox": [ 221, 788, 403, 800 ], "page_idx": 5 }, { "type": "text", "text": " ", "bbox": [ 221, 819, 436, 831 ], "page_idx": 5 }, { "type": "text", "text": "
", "bbox": [ 206, 850, 258, 860 ], "page_idx": 5 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "

\\{rtt}>

", "guess_lang": "txt", "bbox": [ 206, 95, 299, 107 ], "page_idx": 6 }, { "type": "text", "text": "项目 GET 示例 POST 示例", "bbox": [ 176, 126, 623, 139 ], "page_idx": 6 }, { "type": "text", "text": "URL 个数 2 个 (/search-form/ 和 /search/) 1 个 (/search-post/)", "bbox": [ 176, 159, 684, 173 ], "page_idx": 6 }, { "type": "text", "text": "表单方法 method=\"get\" method=\"post\"", "bbox": [ 176, 192, 660, 205 ], "page_idx": 6 }, { "type": "text", "text": "数据传输方式 通过 URL 参数 (?q=...) 通过请求体", "bbox": [ 176, 225, 625, 237 ], "page_idx": 6 }, { "type": "text", "text": "安全性 较低，数据暴露在 URL 中 更安全，数据在请求体中", "bbox": [ 176, 256, 705, 271 ], "page_idx": 6 }, { "type": "text", "text": "CSRF Token 不需要 必须要", "bbox": [ 176, 290, 600, 303 ], "page_idx": 6 }, { "type": "text", "text": "View 函数数量 2 个 1 个 ", "bbox": [ 176, 323, 584, 335 ], "page_idx": 6 }, { "type": "text", "text": "显示与处理 分开处理 合并处理", "bbox": [ 176, 356, 611, 369 ], "page_idx": 6 }, { "type": "text", "text": "(1) 您的两个视图函数", "text_level": 1, "bbox": [ 147, 388, 278, 400 ], "page_idx": 6 }, { "type": "text", "text": "# 显示视图 （表面看只负责显示）", "bbox": [ 146, 419, 344, 431 ], "page_idx": 6 }, { "type": "text", "text": "def search_form(request): ", "bbox": [ 146, 450, 305, 462 ], "page_idx": 6 }, { "type": "text", "text": "return render(request, 'search_form.html') # 但本质上仍是View 层 ", "bbox": [ 161, 481, 563, 494 ], "page_idx": 6 }, { "type": "text", "text": "# 处理视图 （表面看只负责处理）", "bbox": [ 146, 512, 344, 524 ], "page_idx": 6 }, { "type": "text", "text": "def search(request): ", "bbox": [ 146, 543, 270, 555 ], "page_idx": 6 }, { "type": "text", "text": "message $=$ process_request(request.GET) # 处理逻辑 ", "bbox": [ 161, 574, 495, 586 ], "page_idx": 6 }, { "type": "text", "text": "return HttpResponse(message) # 响应生成", "bbox": [ 161, 605, 428, 618 ], "page_idx": 6 }, { "type": "text", "text": "本质：", "text_level": 1, "bbox": [ 147, 636, 183, 646 ], "page_idx": 6 }, { "type": "text", "text": "这两个函数都属于View 层，只是内部逻辑侧重不同。Django 的View 是统一的请求处理器，不强制分离显示与处理。", "bbox": [ 144, 653, 840, 667 ], "page_idx": 6 }, { "type": "text", "text": "(2) 为什么不是两个MVT？", "text_level": 1, "bbox": [ 147, 684, 304, 697 ], "page_idx": 6 }, { "type": "list", "sub_type": "text", "list_items": [ "Model：两个视图可能共享同一个Model（如都查询Article 表）", "Template：search_form 使用模板，search 直接返回响应（动态选择）", "View：都是接收request 并返回响应的函数" ], "bbox": [ 176, 715, 633, 791 ], "page_idx": 6 }, { "type": "text", "text": "创建第一个项目", "text_level": 1, "bbox": [ 147, 820, 428, 850 ], "page_idx": 6 }, { "type": "text", "text": "使用 django-admin 来创建 HelloWorld 项目：", "bbox": [ 147, 868, 413, 881 ], "page_idx": 6 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "django-admin startproject HelloWorld ", "guess_lang": "txt", "bbox": [ 147, 93, 426, 107 ], "page_idx": 7 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "$ cd HelloWorld/ ", "guess_lang": "txt", "bbox": [ 147, 123, 250, 135 ], "page_idx": 7 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "$tree ", "guess_lang": "txt", "bbox": [ 147, 155, 184, 166 ], "page_idx": 7 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "HelloWorld/ #项目根目录", "guess_lang": "txt", "bbox": [ 147, 186, 366, 198 ], "page_idx": 7 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "manage.py #项目管理脚本", "guess_lang": "txt", "bbox": [ 149, 216, 401, 229 ], "page_idx": 7 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "dbsqlite3 #SQLite数据库文件", "guess_lang": "txt", "bbox": [ 149, 247, 420, 260 ], "page_idx": 7 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "—— Pycache_// #Python字节码缓存", "guess_lang": "txt", "bbox": [ 149, 278, 440, 292 ], "page_idx": 7 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "—HelloWorld/#项目配置目录（与项目同名）", "guess_lang": "txt", "bbox": [ 149, 309, 482, 322 ], "page_idx": 7 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "init.py #包标识文件", "guess_lang": "txt", "bbox": [ 164, 340, 379, 354 ], "page_idx": 7 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "—settings.py #项目设置", "guess_lang": "txt", "bbox": [ 164, 370, 364, 384 ], "page_idx": 7 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "├—urls.py #主路由配置 ", "guess_lang": "txt", "bbox": [ 164, 401, 364, 414 ], "page_idx": 7 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "— asgi.py #ASGI 配置 ", "guess_lang": "txt", "bbox": [ 164, 432, 363, 447 ], "page_idx": 7 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "—wsgi.py #WSGI配置 ", "guess_lang": "txt", "bbox": [ 164, 464, 369, 478 ], "page_idx": 7 }, { "type": "text", "text": "目录说明：", "text_level": 1, "bbox": [ 147, 502, 253, 521 ], "page_idx": 7 }, { "type": "text", "text": "项目根目录 (HelloWorld/)：", "bbox": [ 147, 538, 312, 552 ], "page_idx": 7 }, { "type": "table", "img_path": "images/c43fbf5546482fbe70641375fef390807849c110805286d7c5ea772917c5c607.jpg", "table_caption": [], "table_footnote": [], "table_body": "
文件/目录作用
manage.pyDjango命令行工具入口，可让你以各种方式与该Django项目进行交互。用于运行开发服务器、数据库迁移等操作。
db.sql3SQLite 数据库文件（默认数据库，开发环境使用）。
__pycache__IPython字节码缓存目录（自动生成，无需手动修改）。
", "bbox": [ 147, 557, 998, 684 ], "page_idx": 7 }, { "type": "list", "sub_type": "text", "list_items": [ "HelloWorld: 项目的容器。", "HelloWorld/__init__.py: 一个空文件，告诉 Python 该目录是一个 Python 包。", "HelloWorld/asgi.py: 一个 ASGI 兼容的 Web 服务器的入口，以便运行你的项目。", "HelloWorld/settings.py: 该 Django 项目的设置/配置。" ], "bbox": [ 132, 709, 643, 815 ], "page_idx": 7 }, { "type": "text", "text": "", "bbox": [ 183, 841, 194, 848 ], "page_idx": 7 }, { "type": "text", "text": "核心配置文件，包含：", "bbox": [ 213, 858, 344, 871 ], "page_idx": 7 }, { "type": "text", "text": "- 数据库设置 (DATABASES)", "bbox": [ 213, 877, 383, 890 ], "page_idx": 7 }, { "type": "list", "sub_type": "text", "list_items": [ "- 静态文件路径 (STATIC_URL)", "- 应用注册 (INSTALLED_APPS) ", "- 调试模式 (DEBUG=True/False)" ], "bbox": [ 213, 101, 411, 152 ], "page_idx": 8 }, { "type": "text", "text": "HelloWorld/urls.py: 该 Django 项目的 URL 声明; 一份由 Django 驱动的网站\"目录\"。", "bbox": [ 134, 206, 665, 221 ], "page_idx": 8 }, { "type": "text", "text": "主路由配置文件，定义URL 路径与视图的映射关系。", "bbox": [ 169, 263, 482, 277 ], "page_idx": 8 }, { "type": "image", "img_path": "images/a823f7d1709065a5407af080d7f7f97b7690b14cc995738e94875496ffb4c9e6.jpg", "image_caption": [], "image_footnote": [], "bbox": [ 166, 332, 771, 456 ], "page_idx": 8 }, { "type": "text", "text": "HelloWorld/wsgi.py: 一个 WSGI 兼容的 Web 服务器的入口，以便运行你的项目。", "bbox": [ 134, 475, 652, 489 ], "page_idx": 8 }, { "type": "text", "text": "关键文件详解", "text_level": 1, "bbox": [ 147, 517, 292, 536 ], "page_idx": 8 }, { "type": "text", "text": "1. settings.py（核心配置）", "bbox": [ 134, 579, 285, 592 ], "page_idx": 8 }, { "type": "text", "text": "实例", "bbox": [ 134, 609, 166, 621 ], "page_idx": 8 }, { "type": "text", "text": "# HelloWorld/settings.py 示例片段", "bbox": [ 134, 640, 329, 653 ], "page_idx": 8 }, { "type": "text", "text": "# 安全警告：生产环境必须关闭DEBUG！", "bbox": [ 134, 678, 369, 690 ], "page_idx": 8 }, { "type": "text", "text": "DEBUG $=$ True ", "bbox": [ 134, 697, 215, 707 ], "page_idx": 8 }, { "type": "text", "text": "# 允许访问的域名（DEBUG=False 时需配置）", "bbox": [ 134, 734, 389, 746 ], "page_idx": 8 }, { "type": "text", "text": "ALLOWED_HOSTS = [] ", "bbox": [ 134, 752, 255, 764 ], "page_idx": 8 }, { "type": "text", "text": "# 注册的 Django 应用", "bbox": [ 134, 789, 260, 802 ], "page_idx": 8 }, { "type": "text", "text": "INSTALLED_APPS = [ ", "bbox": [ 134, 807, 248, 820 ], "page_idx": 8 }, { "type": "text", "text": "'django.contrib.admin', # 管理员后台", "bbox": [ 147, 826, 359, 838 ], "page_idx": 8 }, { "type": "text", "text": "'django.contrib.auth', # 认证系统", "bbox": [ 147, 845, 341, 857 ], "page_idx": 8 }, { "type": "text", "text": "'django.contrib.contenttypes', ", "bbox": [ 147, 863, 314, 875 ], "page_idx": 8 }, { "type": "text", "text": "'django.contrib.sessions', ", "bbox": [ 147, 882, 287, 892 ], "page_idx": 8 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "'django.contrib.messages', \n'django.contrib(staticfiles', #静态文件处理 \n] \n#数据库配置（默认SQLite） \nDATABASES = { \n 'default': { \n 'ENGINE': 'django.db.backendssqlite3', \n 'NAME': BASE_DIR / 'db.sqlite3', #数据库文件路径} \n} \n#静态文件URL（CSS/JS/图片） \nSTATIC_URL = 'static/'", "guess_lang": "python", "bbox": [ 129, 93, 450, 350 ], "page_idx": 9 }, { "type": "text", "text": "2. urls.py（路由配置）", "text_level": 1, "bbox": [ 134, 366, 263, 379 ], "page_idx": 9 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 134, 397, 168, 410 ], "page_idx": 9 }, { "type": "text", "text": "# HelloWorld/urls.py 示例", "bbox": [ 134, 428, 285, 441 ], "page_idx": 9 }, { "type": "text", "text": "from django.contrib import admin ", "bbox": [ 134, 466, 327, 478 ], "page_idx": 9 }, { "type": "text", "text": "from django.urls import path ", "bbox": [ 134, 483, 300, 495 ], "page_idx": 9 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "urlpatterns $= [$ path('admin／',admin.site.urls)，#后台管理路由 #可在此添加自定义路由，如： #path('blog／',include('blog URLs')) \n]", "bbox": [ 134, 521, 416, 608 ], "page_idx": 9 }, { "type": "text", "text": "3. manage.py（项目管理脚本）", "text_level": 1, "bbox": [ 134, 626, 314, 639 ], "page_idx": 9 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 134, 657, 168, 669 ], "page_idx": 9 }, { "type": "text", "text": "#!/usr/bin/env python ", "bbox": [ 134, 688, 262, 700 ], "page_idx": 9 }, { "type": "text", "text": "import os ", "bbox": [ 134, 707, 193, 718 ], "page_idx": 9 }, { "type": "text", "text": "import sys ", "bbox": [ 134, 725, 196, 737 ], "page_idx": 9 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "if __name__ == \"_main_: \nos.environ.setdefault(\"DJANGO.SettingsMODULE\", \"HelloWorld.Settings\") \nfrom django.core.management import execute_from_command_line \nexecute_from_command_line(sys.argv) ", "guess_lang": "python", "bbox": [ 134, 762, 571, 832 ], "page_idx": 9 }, { "type": "text", "text": "启动服务器", "text_level": 1, "bbox": [ 147, 854, 265, 873 ], "page_idx": 9 }, { "type": "text", "text": "接下来我们进入 HelloWorld 目录输入以下命令，启动服务器：", "bbox": [ 132, 889, 495, 902 ], "page_idx": 9 }, { "type": "text", "text": "0.0.0.0 让其它电脑可连接到开发服务器，8000 为端口号。如果不说明，那么端口号默认为 $8 0 0 0 _ { \\circ }$ ", "bbox": [ 132, 126, 702, 139 ], "page_idx": 10 }, { "type": "text", "text": "在浏览器输入你服务器的 ip（这里我们输入本机 IP 地址： 127.0.0.1:8000） 及端口号。", "bbox": [ 132, 156, 640, 170 ], "page_idx": 10 }, { "type": "text", "text": "常用 django-admin 命令详解", "text_level": 1, "bbox": [ 147, 193, 458, 215 ], "page_idx": 10 }, { "type": "text", "text": "django-admin 是 Django 框架提供的一个命令行工具，它是管理 Django 项目的核心工具。", "bbox": [ 144, 227, 677, 241 ], "page_idx": 10 }, { "type": "text", "text": "无论是创建新项目、运行开发服务器，还是执行数据库迁移，django-admin 都是不可或缺的工具。", "bbox": [ 144, 249, 724, 262 ], "page_idx": 10 }, { "type": "text", "text": "要查看 django-admin 提供的所有命令，可以运行：", "bbox": [ 146, 269, 448, 284 ], "page_idx": 10 }, { "type": "text", "text": "django-admin help ", "bbox": [ 146, 292, 263, 305 ], "page_idx": 10 }, { "type": "text", "text": "1. 创建新项目", "text_level": 1, "bbox": [ 147, 355, 294, 375 ], "page_idx": 10 }, { "type": "text", "text": "django-admin startproject 项目名称", "bbox": [ 134, 417, 339, 429 ], "page_idx": 10 }, { "type": "text", "text": "这个命令会在当前目录下创建一个新的 Django 项目，包含基本的项目结构：", "bbox": [ 132, 447, 579, 460 ], "page_idx": 10 }, { "type": "list", "sub_type": "text", "list_items": [ "manage.py：项目管理脚本", "项目名称/：项目主目录" ], "bbox": [ 176, 479, 368, 521 ], "page_idx": 10 }, { "type": "list", "sub_type": "text", "list_items": [ "o __init__.py", "o settings.py：项目设置文件", "o urls.py：URL 路由配置 ", "o wsgi.py：WSGI 应用入口" ], "bbox": [ 236, 539, 425, 645 ], "page_idx": 10 }, { "type": "text", "text": "2. 创建新应用", "text_level": 1, "bbox": [ 146, 675, 295, 694 ], "page_idx": 10 }, { "type": "text", "text": "虽然通常使用 manage.py 来创建应用，但也可以通过 django-admin：", "bbox": [ 134, 736, 529, 749 ], "page_idx": 10 }, { "type": "text", "text": "django-admin startapp 应用名称", "bbox": [ 134, 768, 319, 780 ], "page_idx": 10 }, { "type": "text", "text": "这会创建一个新的 Django 应用，包含：", "bbox": [ 134, 799, 364, 810 ], "page_idx": 10 }, { "type": "list", "sub_type": "text", "list_items": [ "migrations/：数据库迁移文件目录", "__init__.py", "admin.py：管理后台配置" ], "bbox": [ 176, 829, 408, 904 ], "page_idx": 10 }, { "type": "header", "text": "python3 manage.py runserver 0.0.0.0:8000 ", "bbox": [ 134, 95, 376, 107 ], "page_idx": 10 }, { "type": "list", "sub_type": "text", "list_items": [ "apps.py：应用配置 ", "models.py：数据模型定义", "tests.py：测试代码 ", "views.py：视图函数" ], "bbox": [ 176, 95, 359, 199 ], "page_idx": 11 }, { "type": "text", "text": "models.py ", "bbox": [ 176, 219, 238, 229 ], "page_idx": 11 }, { "type": "text", "text": "定义数据模型，与数据库表对应：", "bbox": [ 176, 250, 374, 261 ], "page_idx": 11 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 178, 281, 208, 292 ], "page_idx": 11 }, { "type": "text", "text": "from django.db import models ", "bbox": [ 176, 312, 349, 323 ], "page_idx": 11 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "class Product/models.Model): name $=$ models.CharField(max_length $\\coloneqq$ 100) price $=$ modelsDecimalField(maxDigits $\\coloneqq$ 10,decimal_places $\\coloneqq$ 2) description $=$ models.TextField() ", "bbox": [ 176, 349, 537, 416 ], "page_idx": 11 }, { "type": "text", "text": "def __str__(self): ", "bbox": [ 189, 441, 287, 453 ], "page_idx": 11 }, { "type": "text", "text": "return self.name ", "bbox": [ 201, 461, 295, 470 ], "page_idx": 11 }, { "type": "text", "text": "views.py ", "bbox": [ 176, 492, 230, 502 ], "page_idx": 11 }, { "type": "text", "text": "处理业务逻辑，返回响应：", "bbox": [ 176, 521, 334, 533 ], "page_idx": 11 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 178, 552, 208, 564 ], "page_idx": 11 }, { "type": "text", "text": "from django.shortcuts import render ", "bbox": [ 176, 583, 383, 595 ], "page_idx": 11 }, { "type": "text", "text": "from .models import Product ", "bbox": [ 176, 602, 342, 613 ], "page_idx": 11 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "def product_list(request):\n products = Product.objects.all()\n return render(request, 'myapp/product_list.html', {'products': products}) ", "guess_lang": "python", "bbox": [ 176, 640, 589, 688 ], "page_idx": 11 }, { "type": "text", "text": "admin.py ", "bbox": [ 176, 708, 233, 719 ], "page_idx": 11 }, { "type": "text", "text": "配置 Django 管理后台：", "bbox": [ 176, 739, 310, 751 ], "page_idx": 11 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 178, 770, 208, 781 ], "page_idx": 11 }, { "type": "text", "text": "from django.contrib import admin ", "bbox": [ 176, 800, 369, 812 ], "page_idx": 11 }, { "type": "text", "text": "from .models import Product ", "bbox": [ 176, 820, 342, 829 ], "page_idx": 11 }, { "type": "text", "text": "@admin.register(Product) ", "bbox": [ 178, 856, 322, 866 ], "page_idx": 11 }, { "type": "text", "text": "3. 检查项目配置", "text_level": 1, "bbox": [ 146, 186, 319, 205 ], "page_idx": 12 }, { "type": "text", "text": "django-admin check ", "bbox": [ 134, 247, 250, 259 ], "page_idx": 12 }, { "type": "text", "text": "这个命令会检查你的 Django 项目是否有配置错误，包括：", "bbox": [ 132, 278, 470, 291 ], "page_idx": 12 }, { "type": "list", "sub_type": "text", "list_items": [ ". 模型定义是否正确 ", "URL 配置是否有效", "模板设置是否正确", "静态文件配置等" ], "bbox": [ 176, 309, 319, 414 ], "page_idx": 12 }, { "type": "text", "text": "4. 数据库迁移 ", "text_level": 1, "bbox": [ 146, 444, 295, 463 ], "page_idx": 12 }, { "type": "text", "text": "Django 使用迁移系统来管理数据库模式变更：", "bbox": [ 134, 505, 400, 517 ], "page_idx": 12 }, { "type": "text", "text": "django-admin makemigrations # 创建迁移文件", "bbox": [ 134, 537, 401, 548 ], "page_idx": 12 }, { "type": "text", "text": "django-admin migrate # 应用迁移到数据库", "bbox": [ 134, 568, 401, 579 ], "page_idx": 12 }, { "type": "text", "text": "5. 创建超级用户", "text_level": 1, "bbox": [ 146, 608, 317, 627 ], "page_idx": 12 }, { "type": "text", "text": "django-admin createsuperuser ", "bbox": [ 134, 671, 305, 681 ], "page_idx": 12 }, { "type": "text", "text": "这个命令会引导你创建一个可以访问 Django 管理后台的超级用户。", "bbox": [ 132, 701, 524, 714 ], "page_idx": 12 }, { "type": "text", "text": "6.启动开发服务器", "text_level": 1, "bbox": [ 146, 743, 336, 762 ], "page_idx": 12 }, { "type": "text", "text": "django-admin runserver ", "bbox": [ 134, 804, 273, 816 ], "page_idx": 12 }, { "type": "text", "text": "基本语法:", "bbox": [ 134, 835, 196, 847 ], "page_idx": 12 }, { "type": "text", "text": "python manage.py runserver [IP:端口] ", "bbox": [ 134, 866, 347, 879 ], "page_idx": 12 }, { "type": "header", "text": "class ProductAdmin(admin.ModelAdmin): ", "bbox": [ 176, 95, 410, 107 ], "page_idx": 12 }, { "type": "header", "text": "list_display $=$ ('name', 'price') ", "bbox": [ 189, 112, 351, 124 ], "page_idx": 12 }, { "type": "text", "text": "扩展目录（非自动生成，但常用）", "text_level": 1, "bbox": [ 146, 101, 477, 120 ], "page_idx": 13 }, { "type": "text", "text": "HelloWorld/ ", "bbox": [ 134, 135, 206, 145 ], "page_idx": 13 }, { "type": "list", "sub_type": "text", "list_items": [ "├── apps/ # 推荐：存放所有自定义应用", "│ └── blog/ # 示例应用", "├── static/ # 静态文件（CSS/JS/图片）", "├── media/ # 用户上传文件", "├── templates/ # 全局模板目录", "└── requirements.txt # 项目依赖列表" ], "bbox": [ 136, 165, 410, 332 ], "page_idx": 13 }, { "type": "text", "text": "1. apps/ 目录（推荐结构）", "text_level": 1, "bbox": [ 147, 362, 421, 382 ], "page_idx": 13 }, { "type": "text", "text": "将应用集中管理，避免散落在项目根目录。", "bbox": [ 134, 423, 386, 436 ], "page_idx": 13 }, { "type": "text", "text": "需在 settings.py 中配置 Python 路径：", "bbox": [ 134, 454, 347, 467 ], "page_idx": 13 }, { "type": "text", "text": "import sys ", "bbox": [ 134, 486, 194, 497 ], "page_idx": 13 }, { "type": "text", "text": "sys.path.insert(0, os.path.join(BASE_DIR, 'apps'))", "bbox": [ 134, 516, 401, 527 ], "page_idx": 13 }, { "type": "text", "text": "2. 静态文件与媒体文件", "text_level": 1, "bbox": [ 144, 558, 389, 577 ], "page_idx": 13 }, { "type": "list", "sub_type": "text", "list_items": [ "static/：存放 CSS、JavaScript、图片等，通过 STATIC_URL 访问。", "media/：用户上传的文件（如头像），通过 MEDIA_URL 访问。需配置服务器在开发时提供访问：", ". # urls.py（仅开发环境）", "from django.conf import settings ", "from django.conf.urls.static import static " ], "bbox": [ 176, 619, 771, 783 ], "page_idx": 13 }, { "type": "text", "text": "urlpatterns $+ =$ static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT) ", "bbox": [ 134, 804, 584, 818 ], "page_idx": 13 }, { "type": "text", "text": "一个项目可以由多个应用", "text_level": 1, "bbox": [ 147, 873, 400, 892 ], "page_idx": 13 }, { "type": "list", "sub_type": "text", "list_items": [ "myproject/ ", "├── manage.py ", "├── requirements.txt ", "├── static/ ", "│ ── css/ ├ ", "│ ── js/ ├ ", "│ └── images/ ", "├── media/ ", "├── templates/ ", "│ └── base.html ", "└── myproject/ ", "── __init__.py ├", "── settings.py ├ ", "── urls.py ├ ", "── wsgi.py ├ ", "└── asgi.py ", "└── myapp1/ ", "── migrations/├ ", "── templates/ ├ ", "│ └── myapp1/ ", "── __init__.py ├", "── admin.py ├ ", "── apps.py ├ ", "── models.py ├ ", "── tests.py ├ " ], "bbox": [ 134, 93, 255, 882 ], "page_idx": 14 }, { "type": "list", "sub_type": "text", "list_items": [ "── urls.py ├ ", "└── views.py " ], "bbox": [ 147, 93, 221, 137 ], "page_idx": 15 }, { "type": "text", "text": "└── myapp2/ ", "bbox": [ 136, 156, 211, 168 ], "page_idx": 15 }, { "type": "text", "text": "└── ... (类似结构) ", "bbox": [ 147, 187, 248, 200 ], "page_idx": 15 }, { "type": "text", "text": "实践建议", "text_level": 1, "bbox": [ 147, 218, 205, 230 ], "page_idx": 15 }, { "type": "list", "sub_type": "text", "list_items": [ "1. 项目与应用分离：保持每个应用的独立性，便于复用", "2. 环境配置：使用不同的 settings 文件区分开发和生产环境", "3. 静态文件管理：开发时使用 STATICFILES_DIRS，生产时使用 collectstatic", "4. URL 设计：在应用级别定义 URL，然后在项目级别包含", "5. 模板组织：为每个应用创建子目录存放模板" ], "bbox": [ 176, 249, 618, 386 ], "page_idx": 15 }, { "type": "text", "text": "生产环境vs 开发环境差异", "text_level": 1, "bbox": [ 146, 404, 304, 418 ], "page_idx": 15 }, { "type": "table", "img_path": "images/d1a1f6ba9036662acf8c0bf0be0cbc4df02f97c028a0669d048704990c5b36eb.jpg", "table_caption": [], "table_footnote": [], "table_body": "
文件/配置开发环境生产环境
DEBUGTrue（显示错误详情）False（隐藏错误，记录到日志）
数据库SQLite（默认）PostgreSQL/MySQL（性能优化）
静态文件runserver 自动服务使用 collectstatic 收集到 CDN
ALLOWED_HOSTS空列表或 ['localhost']必须配置域名（如 ['example.com'])
", "bbox": [ 147, 432, 998, 657 ], "page_idx": 15 }, { "type": "text", "text": "path() 函数", "text_level": 1, "bbox": [ 147, 695, 309, 722 ], "page_idx": 15 }, { "type": "text", "text": "Django path() 可以接收四个参数，分别是两个必选参数：route、view 和两个可选参数：kwargs、name。", "bbox": [ 146, 728, 766, 743 ], "page_idx": 15 }, { "type": "text", "text": "语法格式：", "bbox": [ 147, 747, 203, 760 ], "page_idx": 15 }, { "type": "text", "text": "path(route, view, kwargs=None, name=None) ", "bbox": [ 147, 777, 460, 789 ], "page_idx": 15 }, { "type": "text", "text": "route：字符串，定义URL 的路径部分。可以包含变量，例如，以从URL 中捕获参数并将其传递给视图函数。", "bbox": [ 144, 806, 847, 837 ], "page_idx": 15 }, { "type": "text", "text": "view：视图函数，处理与给定路由匹配的请求。可以是一个函数或一个基于类的视图。", "bbox": [ 146, 843, 658, 856 ], "page_idx": 15 }, { "type": "text", "text": "kwargs（可选）：一个字典，包含传递给视图函数的额外关键字参数。", "bbox": [ 146, 862, 568, 875 ], "page_idx": 15 }, { "type": "text", "text": "name（可选）：为URL 路由指定一个唯一的名称，以便在代码的其他地方引用它。这对于在模板中生成URL 或在代码中进行重定向等操作非常有用。", "bbox": [ 144, 93, 848, 126 ], "page_idx": 16 }, { "type": "text", "text": "这样我们就完成了使用模板来输出数据，从而实现数据与视图分离。", "bbox": [ 146, 131, 547, 145 ], "page_idx": 16 }, { "type": "text", "text": "接下来我们将具体介绍模板中常用的语法规则。", "bbox": [ 146, 149, 428, 162 ], "page_idx": 16 }, { "type": "text", "text": "Django 模板", "text_level": 1, "bbox": [ 147, 193, 329, 222 ], "page_idx": 16 }, { "type": "text", "text": "Django 的模板系统（Template System）是用于将业务逻辑（Python）与展示层（HTML）分离的核心组件，它允许开发者通过简单的标签和变量动态生成 HTML 页面。", "bbox": [ 144, 230, 840, 262 ], "page_idx": 16 }, { "type": "text", "text": "在上一章节中我们使用 django.http.HttpResponse() 来输出 \"Hello World！\"，该方式将数据与视图混合在一起，不符合 Django 的 MVT 思想。", "bbox": [ 144, 269, 843, 302 ], "page_idx": 16 }, { "type": "text", "text": "本章节我们将为大家详细介绍Django 模板的应用，模板是一个文本，用于分离文档的表现形式和内容。", "bbox": [ 146, 309, 757, 323 ], "page_idx": 16 }, { "type": "table", "img_path": "images/d6715d65fc28226ad77843e37b6ae208fe41f5917292f96ae26d2c7786e130c3.jpg", "table_caption": [], "table_footnote": [], "table_body": "
功能语法/示例适用场景
变量渲染{\\ variable }动态显示数据
逻辑控制{% if %}, {% for %}条件/循环渲染
模板继承{% extends %}, {% block %}避免重复 HTML 结构
静态文件{% static 'path' %}加载 CSS/JS/图片
自定义过滤器@register.filter扩展模板功能
", "bbox": [ 147, 329, 1000, 521 ], "page_idx": 16 }, { "type": "text", "text": "Django 模板标签", "text_level": 1, "bbox": [ 147, 577, 389, 607 ], "page_idx": 16 }, { "type": "text", "text": "变量", "text_level": 1, "bbox": [ 147, 621, 201, 640 ], "page_idx": 16 }, { "type": "text", "text": "模板语法：", "bbox": [ 147, 653, 211, 668 ], "page_idx": 16 }, { "type": "text", "text": "view：｛\"HTML 变量名\" : \"views 变量名\"｝ ", "bbox": [ 147, 683, 413, 697 ], "page_idx": 16 }, { "type": "text", "text": "HTML：｛｛变量名｝｝ ", "bbox": [ 147, 712, 275, 726 ], "page_idx": 16 }, { "type": "text", "text": "列表", "text_level": 1, "bbox": [ 147, 747, 213, 769 ], "page_idx": 16 }, { "type": "text", "text": "templates 中的 runoob.html 中，可以用 . 索引下标取出对应的元素。", "bbox": [ 146, 782, 552, 796 ], "page_idx": 16 }, { "type": "text", "text": "HelloWorld/HelloWorld/views.py 文件代码：", "bbox": [ 146, 800, 472, 815 ], "page_idx": 16 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "from django.shortcuts import render \ndef runoob(request): \n views_list = [\"菜鸟教程1\", \"菜鸟教程2\", \"菜鸟教程3\"] \n return render(request, \"runoob.html\", {\"views_list\": views_list}) ", "guess_lang": "python", "bbox": [ 147, 822, 675, 892 ], "page_idx": 16 }, { "type": "text", "text": "templates 中的 runoob.html 中，可以用 .键 取出对应的值。", "bbox": [ 146, 93, 497, 107 ], "page_idx": 17 }, { "type": "text", "text": "过滤器", "text_level": 1, "bbox": [ 146, 122, 225, 142 ], "page_idx": 17 }, { "type": "text", "text": "模板语法：", "bbox": [ 146, 156, 203, 168 ], "page_idx": 17 }, { "type": "text", "text": "{{ 变量名 | 过滤器：可选参数 }}", "bbox": [ 147, 185, 354, 198 ], "page_idx": 17 }, { "type": "text", "text": "模板过滤器可以在变量被显示前修改它，过滤器使用管道字符，如下所示：", "bbox": [ 146, 214, 586, 227 ], "page_idx": 17 }, { "type": "text", "text": "safe ", "bbox": [ 147, 233, 179, 243 ], "page_idx": 17 }, { "type": "text", "text": "将字符串标记为安全，不需要转义。", "bbox": [ 146, 250, 357, 263 ], "page_idx": 17 }, { "type": "text", "text": "要保证 views.py 传过来的数据绝对安全，才能用 safe。", "bbox": [ 146, 269, 470, 282 ], "page_idx": 17 }, { "type": "text", "text": "和后端 views.py 的 mark_safe 效果相同。", "bbox": [ 146, 288, 391, 300 ], "page_idx": 17 }, { "type": "text", "text": "Django 会自动对 views.py 传到HTML文件中的标签语法进行转义，令其语义失效。加safe 过滤器是告诉Django 该", "bbox": [ 144, 307, 835, 319 ], "page_idx": 17 }, { "type": "text", "text": "数据是安全的，不必对其进行转义，可以让该数据语义生效。", "bbox": [ 146, 326, 505, 338 ], "page_idx": 17 }, { "type": "text", "text": "if/else 标签", "text_level": 1, "bbox": [ 146, 353, 275, 373 ], "page_idx": 17 }, { "type": "text", "text": "基本语法格式如下：", "bbox": [ 146, 386, 265, 399 ], "page_idx": 17 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "$\\{\\% \\text{if condition}\\}$ display{ $\\%$ endif} ", "bbox": [ 147, 414, 357, 458 ], "page_idx": 17 }, { "type": "text", "text": "或者：", "bbox": [ 146, 474, 184, 486 ], "page_idx": 17 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "$\\{\\%$ if condition1 $\\}$ . display 1{% elif condition2 $\\}$ . display 2{% else $\\}$ display 3{%endif $\\}$ ", "bbox": [ 147, 502, 431, 604 ], "page_idx": 17 }, { "type": "text", "text": "根据条件判断是否输出。if/else 支持嵌套。", "bbox": [ 146, 621, 396, 633 ], "page_idx": 17 }, { "type": "text", "text": "$\\{ \\%$ if %} 标签接受 and ， or 或者 not 关键字来对多个变量做判断 ，或者对变量取反（ not )，例如：", "bbox": [ 146, 639, 729, 653 ], "page_idx": 17 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "$\\{\\%$ if athlete_list and coach_list $\\}$ athletes和coaches变量都是可用的。 $\\{\\%$ endif $\\}$ ", "bbox": [ 147, 667, 521, 711 ], "page_idx": 17 }, { "type": "text", "text": "遍历字典: 可以直接用字典.items 方法，用变量的解包分别获取键和值。", "bbox": [ 146, 727, 571, 739 ], "page_idx": 17 }, { "type": "text", "text": "for 标签 ", "text_level": 1, "bbox": [ 146, 791, 238, 810 ], "page_idx": 17 }, { "type": "text", "text": "$\\{ \\%$ for $\\% \\}$ 允许我们在一个序列上迭代。", "bbox": [ 146, 825, 376, 838 ], "page_idx": 17 }, { "type": "text", "text": "与 Python 的 for 语句的情形类似，循环语法是 for X in Y ，Y 是要迭代的序列而 X 是在每一个特定的循环中使用的变量名称。", "bbox": [ 144, 844, 836, 873 ], "page_idx": 17 }, { "type": "text", "text": "每一次循环中，模板系统会渲染在 $6 \\%$ for $\\% 3$ 和 $6 \\%$ endfor $\\% 3$ 之间的所有内容。", "bbox": [ 146, 881, 648, 894 ], "page_idx": 17 }, { "type": "text", "text": "例如，给定一个运动员列表 athlete_list 变量，我们可以使用下面的代码来显示这个列表：", "bbox": [ 146, 95, 606, 105 ], "page_idx": 18 }, { "type": "text", "text": "{% empty %} ", "bbox": [ 146, 112, 233, 124 ], "page_idx": 18 }, { "type": "text", "text": "可选的 {% empty $\\% \\}$ 从句：在循环为空的时候执行（即 in 后面的参数布尔值为 False ）。", "bbox": [ 146, 131, 670, 143 ], "page_idx": 18 }, { "type": "text", "text": "注释标签 ", "text_level": 1, "bbox": [ 147, 159, 248, 179 ], "page_idx": 18 }, { "type": "text", "text": "Django 注释使用 {# #}。", "bbox": [ 146, 193, 285, 206 ], "page_idx": 18 }, { "type": "text", "text": "{# 这是一个注释 #}", "bbox": [ 147, 221, 268, 234 ], "page_idx": 18 }, { "type": "text", "text": "include 标签 ", "text_level": 1, "bbox": [ 147, 256, 292, 278 ], "page_idx": 18 }, { "type": "text", "text": "{% include %} 标签允许在模板中包含其它的模板的内容。", "bbox": [ 146, 291, 485, 304 ], "page_idx": 18 }, { "type": "text", "text": "下面这个例子都包含了 nav.html 模板：", "bbox": [ 147, 310, 374, 322 ], "page_idx": 18 }, { "type": "text", "text": "{% include \"nav.html\" %} ", "bbox": [ 147, 338, 332, 351 ], "page_idx": 18 }, { "type": "text", "text": "csrf_token ", "text_level": 1, "bbox": [ 147, 373, 307, 395 ], "page_idx": 18 }, { "type": "text", "text": "csrf_token 用于form表单中，作用是跨站请求伪造保护。", "bbox": [ 146, 407, 482, 419 ], "page_idx": 18 }, { "type": "text", "text": "如果不用 $\\{ \\%$ csrf_token $\\% \\}$ 标签，在用 form 表单时，要再次跳转页面会报403 权限错误。", "bbox": [ 146, 425, 684, 437 ], "page_idx": 18 }, { "type": "text", "text": "用了{% csrf_token %} 标签，在 form 表单提交数据时，才会成功。", "bbox": [ 146, 444, 544, 456 ], "page_idx": 18 }, { "type": "text", "text": "自定义标签和过滤器", "text_level": 1, "bbox": [ 149, 468, 431, 493 ], "page_idx": 18 }, { "type": "list", "sub_type": "text", "list_items": [ "1、在应用目录下创建 templatetags 目录(与 templates 目录同级，目录名只能是 templatetags)", "4、利用装饰器 $@$ register.filter 自定义过滤器。" ], "bbox": [ 146, 502, 710, 533 ], "page_idx": 18 }, { "type": "text", "text": "注意：装饰器的参数最多只能有 2 个。 ", "bbox": [ 146, 539, 371, 551 ], "page_idx": 18 }, { "type": "text", "text": "4、利用装饰器 @register.filter 自定义过滤器。", "bbox": [ 146, 558, 418, 570 ], "page_idx": 18 }, { "type": "text", "text": "注意：装饰器的参数最多只能有 2 个。 ", "bbox": [ 146, 576, 371, 588 ], "page_idx": 18 }, { "type": "text", "text": "@register.filterdef my_filter(v1, v2): ", "bbox": [ 147, 604, 436, 618 ], "page_idx": 18 }, { "type": "text", "text": "return v1 * v2 ", "bbox": [ 178, 634, 287, 645 ], "page_idx": 18 }, { "type": "text", "text": "5、利用装饰器 @register.simple_tag 自定义标签。", "bbox": [ 146, 664, 445, 677 ], "page_idx": 18 }, { "type": "text", "text": "配置静态文件", "text_level": 1, "bbox": [ 147, 688, 337, 712 ], "page_idx": 18 }, { "type": "text", "text": "1、在项目根目录下创建 statics 目录。", "bbox": [ 146, 722, 369, 734 ], "page_idx": 18 }, { "type": "image", "img_path": "images/7a0bccfdc891cb8db6929d9ee4656cf5853f50e3339e9658e86f85cd0a8ec3cd.jpg", "image_caption": [], "image_footnote": [], "bbox": [ 147, 737, 364, 866 ], "page_idx": 18 }, { "type": "text", "text": "2、在 settings 文件的最下方配置添加以下配置：", "bbox": [ 146, 871, 431, 883 ], "page_idx": 18 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "STATIC_url $=$ \"/static/'#别名 \nSTATICFILES_DIRS $=$ [os.path.join(Base_DIR，\"statics\")，]", "bbox": [ 147, 93, 453, 165 ], "page_idx": 19 }, { "type": "list", "sub_type": "text", "list_items": [ "3、在 statics 目录下创建 css 目录，js 目录，images 目录，plugins 目录， 分别放 css 文件，js 文件，图片，插件。", "4、把 bootstrap 框架放入插件目录 plugins。", "5、在 HTML 文件的 head 标签中引入 bootstrap。" ], "bbox": [ 144, 181, 826, 231 ], "page_idx": 19 }, { "type": "text", "text": "注意：此时引用路径中的要用配置文件中的别名static，而不是目录 statics。", "bbox": [ 146, 237, 594, 250 ], "page_idx": 19 }, { "type": "text", "text": "模板继承", "text_level": 1, "bbox": [ 146, 281, 275, 306 ], "page_idx": 19 }, { "type": "text", "text": "模板可以用继承的方式来实现复用，减少冗余内容。", "bbox": [ 144, 317, 452, 329 ], "page_idx": 19 }, { "type": "text", "text": "网页的头部和尾部内容一般都是一致的，我们就可以通过模板继承来实现复用。", "bbox": [ 146, 336, 611, 348 ], "page_idx": 19 }, { "type": "text", "text": "父模板用于放置可重复利用的内容，子模板继承父模板的内容，并放置自己的内容。。", "bbox": [ 146, 355, 652, 367 ], "page_idx": 19 }, { "type": "text", "text": "父模板", "text_level": 1, "bbox": [ 147, 382, 223, 401 ], "page_idx": 19 }, { "type": "text", "text": "标签 block...endblock: 父模板中的预留区域，该区域留给子模板填充差异性的内容，不同预留区域名字不能相同。", "bbox": [ 144, 416, 821, 429 ], "page_idx": 19 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "$\\{\\% \\text{block} \\text{名称} \\% \\}$ 预留给子模板的区域，可以设置设置默认内容 $\\{\\% \\text{endblock} \\text{名称} \\% \\}$ ", "bbox": [ 147, 445, 662, 458 ], "page_idx": 19 }, { "type": "text", "text": "子模板", "text_level": 1, "bbox": [ 147, 480, 223, 500 ], "page_idx": 19 }, { "type": "text", "text": "子模板使用标签extends 继承父模板：", "bbox": [ 147, 514, 371, 527 ], "page_idx": 19 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "% extends \"父模板路径\"%}", "guess_lang": "txt", "bbox": [ 147, 544, 326, 556 ], "page_idx": 19 }, { "type": "text", "text": "子模板如果没有设置父模板预留区域的内容，则使用在父模板设置的默认内容，当然也可以都不设置，就为空。", "bbox": [ 146, 573, 800, 585 ], "page_idx": 19 }, { "type": "text", "text": "子模板设置父模板预留区域的内容：", "bbox": [ 147, 590, 357, 602 ], "page_idx": 19 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "{ $\\%$ block名称 $\\%$ }内容{ $\\%$ endblock名称 $\\%$ }", "bbox": [ 147, 621, 448, 633 ], "page_idx": 19 }, { "type": "text", "text": "Django 模型使用自带的 ORM。", "bbox": [ 146, 650, 329, 662 ], "page_idx": 19 }, { "type": "text", "text": "对象关系映射（Object Relational Mapping，简称ORM ）用于实现面向对象编程语言里不同类型系统的数据之间的转换。", "bbox": [ 144, 671, 843, 702 ], "page_idx": 19 }, { "type": "text", "text": "ORM 在业务逻辑层和数据库层之间充当了桥梁的作用。", "bbox": [ 146, 711, 473, 722 ], "page_idx": 19 }, { "type": "text", "text": "ORM 是通过使用描述对象和数据库之间的映射的元数据，将程序中的对象自动持久化到数据库中。", "bbox": [ 146, 732, 727, 745 ], "page_idx": 19 }, { "type": "text", "text": "ORM 解析过程:", "bbox": [ 147, 772, 243, 785 ], "page_idx": 19 }, { "type": "list", "sub_type": "text", "list_items": [ "1、ORM 会将 Python 代码转成为 SQL 语句。", "2、SQL 语句通过 pymysql 传送到数据库服务端。", "3、在数据库中执行 SQL 语句并将结果返回。" ], "bbox": [ 134, 791, 423, 865 ], "page_idx": 19 }, { "type": "image", "img_path": "images/89ff050f91c03b4570c077c1d5a0b35eba5235ff5bcb76f7b6a8328a7ce6d1c7.jpg", "image_caption": [], "image_footnote": [], "bbox": [ 157, 91, 963, 218 ], "page_idx": 20 }, { "type": "text", "text": "ORM 对应关系表：", "bbox": [ 147, 237, 257, 249 ], "page_idx": 20 }, { "type": "image", "img_path": "images/e3b1faa6363d2686aa3e435194c96d28a466d037563692d969fb0f4eb9f90257.jpg", "image_caption": [], "image_footnote": [], "bbox": [ 193, 293, 793, 495 ], "page_idx": 20 }, { "type": "text", "text": "数据库配置", "text_level": 1, "bbox": [ 147, 558, 218, 570 ], "page_idx": 20 }, { "type": "text", "text": "ORM 无法操作到数据库级别，只能操作到数据表", "bbox": [ 146, 589, 438, 602 ], "page_idx": 20 }, { "type": "text", "text": "我们在项目的 settings.py 文件中找到 DATABASES 配置项，将其信息修改为：", "bbox": [ 146, 651, 584, 664 ], "page_idx": 20 }, { "type": "text", "text": "HelloWorld/HelloWorld/settings.py: 文件代码：", "bbox": [ 146, 682, 415, 695 ], "page_idx": 20 }, { "type": "text", "text": "DATABASES $=$ { 'default': { 'ENGINE': 'django.db.backends.mysql', # 数 据 库 引 擎 'NAME': 'runoob', # 数 据 库 名 称 'HOST':'127.0.0.1', # 数据库地址，本机 ip 地址 127.0.0.1 'PORT': 3306, # 端口 'USER': 'root', # 数据库用户名 'PASSWORD': '123456',# 数据库密码 } }", "bbox": [ 144, 713, 848, 764 ], "page_idx": 20 }, { "type": "text", "text": "上面包含数据库名称和用户的信息，它们与 MySQL 中对应数据库和用户的设置相同。Django 根据这一设置，与 MySQL中相应的数据库和用户连接起来。", "bbox": [ 144, 781, 848, 812 ], "page_idx": 20 }, { "type": "text", "text": "接下来，告诉 Django 使用 pymysql 模块连接 mysql 数据库：", "bbox": [ 146, 831, 490, 844 ], "page_idx": 20 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 862, 179, 873 ], "page_idx": 20 }, { "type": "text", "text": "# 在与 settings.py 同级目录下的 __init__.py 中引入模块和进行配置", "bbox": [ 144, 93, 534, 109 ], "page_idx": 21 }, { "type": "text", "text": "import pymysql", "bbox": [ 146, 112, 238, 124 ], "page_idx": 21 }, { "type": "text", "text": "pymysql.install_as_MySQLdb() ", "bbox": [ 146, 131, 317, 143 ], "page_idx": 21 }, { "type": "text", "text": "定义模型", "text_level": 1, "bbox": [ 146, 218, 275, 243 ], "page_idx": 21 }, { "type": "text", "text": "创建 APP", "text_level": 1, "bbox": [ 146, 261, 255, 280 ], "page_idx": 21 }, { "type": "text", "text": "Django 规定，如果要使用模型，必须要创建一个 app。我们使用以下命令创建一个 TestModel 的 app:", "bbox": [ 144, 294, 751, 307 ], "page_idx": 21 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "django-admin startapp TestModel ", "guess_lang": "txt", "bbox": [ 146, 323, 386, 336 ], "page_idx": 21 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "# models.py from django.db import models class Test(model.Model): name = models.CharField(max_length=20) ", "guess_lang": "python", "bbox": [ 146, 353, 705, 384 ], "page_idx": 21 }, { "type": "text", "text": "以上的类名代表了数据库表名，且继承了models.Model，类里面的字段代表数据表中的字段(name)，数据类型则由CharField（相当于 varchar）、DateField（相当于 datetime）， max_length 参数限定长度。", "bbox": [ 144, 390, 830, 423 ], "page_idx": 21 }, { "type": "text", "text": "在命令行中运行：", "bbox": [ 146, 428, 250, 439 ], "page_idx": 21 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "$ python3 manage.py migrate # 创建表结构", "guess_lang": "txt", "bbox": [ 146, 457, 458, 469 ], "page_idx": 21 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "$ python3 manage.py makemigrations TestModel # 让 Django 知道我们在我们的模型有一些变更", "guess_lang": "txt", "bbox": [ 146, 486, 776, 499 ], "page_idx": 21 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "$ python3 manage.py migrate TestModel # 创建表结构", "guess_lang": "txt", "bbox": [ 146, 516, 532, 529 ], "page_idx": 21 }, { "type": "text", "text": "看到几行 \"Creating table…\" 的字样，你的数据表就创建好了。", "bbox": [ 144, 543, 608, 558 ], "page_idx": 21 }, { "type": "text", "text": "Creating tables ... ", "bbox": [ 146, 563, 275, 576 ], "page_idx": 21 }, { "type": "text", "text": "", "bbox": [ 146, 586, 176, 594 ], "page_idx": 21 }, { "type": "text", "text": "Creating table TestModel_test #我们自定义的表", "bbox": [ 144, 600, 505, 614 ], "page_idx": 21 }, { "type": "text", "text": "", "bbox": [ 146, 624, 176, 631 ], "page_idx": 21 }, { "type": "text", "text": "表名组成结构为：应用名_类名（如：TestModel_test）。", "bbox": [ 144, 636, 576, 652 ], "page_idx": 21 }, { "type": "text", "text": "注意：尽管我们没有在 models 给表设置主键，但是 Django 会自动添加一个 id 作为主键。", "bbox": [ 144, 653, 826, 670 ], "page_idx": 21 }, { "type": "text", "text": "添加数据", "text_level": 1, "bbox": [ 146, 673, 221, 688 ], "page_idx": 21 }, { "type": "text", "text": "添加数据需要先创建对象，然后再执行 save 函数，相当于SQL中的INSERT：", "bbox": [ 144, 692, 727, 707 ], "page_idx": 21 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "- - coding: utf-8 - ", "guess_lang": "txt", "bbox": [ 146, 709, 300, 724 ], "page_idx": 21 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "from django.http import HttpResponse ", "guess_lang": "python", "bbox": [ 146, 747, 428, 762 ], "page_idx": 21 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "from TestModel.models import Test ", "guess_lang": "python", "bbox": [ 146, 785, 406, 799 ], "page_idx": 21 }, { "type": "text", "text": "# 数据库操作", "text_level": 1, "bbox": [ 146, 822, 252, 837 ], "page_idx": 21 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "def testdb(request): ", "guess_lang": "txt", "bbox": [ 146, 841, 292, 854 ], "page_idx": 21 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "test1 = Test(name='runoob') ", "guess_lang": "txt", "bbox": [ 161, 859, 366, 873 ], "page_idx": 21 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "test1.save() ", "guess_lang": "txt", "bbox": [ 163, 877, 248, 891 ], "page_idx": 21 }, { "type": "text", "text": "return HttpResponse(\"

数据添加成功！

\")", "bbox": [ 164, 93, 524, 109 ], "page_idx": 22 }, { "type": "text", "text": "更新数据", "text_level": 1, "bbox": [ 149, 112, 221, 127 ], "page_idx": 22 }, { "type": "text", "text": "修改数据可以使用 save() 或 update():", "bbox": [ 147, 130, 428, 145 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "- -coding: utf-8 - ", "guess_lang": "txt", "bbox": [ 147, 149, 300, 162 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "from django.http import HttpResponse ", "guess_lang": "python", "bbox": [ 147, 186, 428, 200 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "from TestModel.models import Test ", "guess_lang": "python", "bbox": [ 147, 223, 406, 237 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [ "# 数据库操作" ], "code_body": "def testdb(request): ", "guess_lang": "txt", "bbox": [ 147, 279, 292, 293 ], "page_idx": 22 }, { "type": "text", "text": "# 修改其中一个 $\\mathrm { i } { \\mathsf { d } } { = } 1$ 的 name 字段，再 save，相当于 SQL 中的 UPDATE", "bbox": [ 163, 297, 695, 312 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "test1 = Test.objects.get(id=1) ", "guess_lang": "python", "bbox": [ 163, 316, 371, 330 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "test1.name = 'Google' ", "guess_lang": "python", "bbox": [ 164, 335, 322, 348 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "test1.save() ", "guess_lang": "txt", "bbox": [ 164, 354, 248, 367 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "# 另外一种方式", "guess_lang": "txt", "bbox": [ 164, 390, 285, 405 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "Test.objects.filter(id=1).update(name='Google') ", "guess_lang": "python", "bbox": [ 164, 407, 512, 423 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "修改所有的列", "guess_lang": "txt", "bbox": [ 164, 445, 285, 460 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "Test.objects.all().update(name='Google') ", "guess_lang": "txt", "bbox": [ 164, 464, 468, 479 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "return HttpResponse(\"/

修改成功

\")", "guess_lang": "lua", "bbox": [ 164, 501, 470, 517 ], "page_idx": 22 }, { "type": "text", "text": "删除数据", "text_level": 1, "bbox": [ 147, 520, 221, 533 ], "page_idx": 22 }, { "type": "text", "text": "删除数据库中的对象只需调用该对象的delete()方法即可：", "bbox": [ 147, 538, 588, 552 ], "page_idx": 22 }, { "type": "text", "text": "Django 表单", "text_level": 1, "bbox": [ 147, 588, 359, 619 ], "page_idx": 22 }, { "type": "text", "text": "HTML表单是网站交互性的经典方式。 本章将介绍如何用Django对用户提交的表单数据进行处理。", "bbox": [ 146, 638, 729, 652 ], "page_idx": 22 }, { "type": "text", "text": "HTTP 请求", "text_level": 1, "bbox": [ 147, 663, 302, 687 ], "page_idx": 22 }, { "type": "text", "text": "HTTP协议以\"请求－回复\"的方式工作。客户发送请求时，可以在请求中附加数据。服务器通过解析请求，就可以获得客户传来的数据，并根据URL来提供特定的服务。", "bbox": [ 146, 697, 843, 728 ], "page_idx": 22 }, { "type": "text", "text": "GET 方法", "text_level": 1, "bbox": [ 147, 746, 257, 765 ], "page_idx": 22 }, { "type": "text", "text": "用户提交了表单，服务器解析表单并回复", "bbox": [ 147, 781, 468, 796 ], "page_idx": 22 }, { "type": "text", "text": "我们在之前的项目中创建一个 search.py 文件，用于接收用户的请求：", "bbox": [ 146, 801, 557, 814 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "from django.http import HttpResponse ", "guess_lang": "python", "bbox": [ 147, 822, 378, 835 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "from django.shortcuts import render ", "guess_lang": "python", "bbox": [ 147, 845, 364, 856 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "#表单 ", "guess_lang": "txt", "bbox": [ 147, 866, 189, 876 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "def search_form(request): ", "guess_lang": "txt", "bbox": [ 147, 887, 304, 898 ], "page_idx": 22 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "return render(request, 'search_form.html') \n#接收请求数据 \ndef search(request): \n request_encoding='utf-8' \n if 'q' in request.GET and request.GET['q']: \n message = '你搜索的内容为: ' + request.GET['q'] \n else: \n message = '你提交了空表单' \n return HttpResponse(message) \n在模板目录templates中添加search_form.html表单： \n/HelloWorld/template/search_form.html文件代码： \n \n \n \n \n菜鸟教程(runob.com) \n \n \n
\n \n \n
\n \n \nurls.py规则修改为如下形式： \n/HelloWorld/HelloWorld URLs.py文件代码： \nfrom django.conf.urls import url \nfrom . import views,testdb,search \nurlpatterns = [url(r'^hello/$', views.runoob),url(r'^testdb/$', testdb.testdb),url(r'^search-form/$', search.search_form),url(r'^search/$', search.search),]", "guess_lang": "python", "bbox": [ 147, 91, 468, 858 ], "page_idx": 23 }, { "type": "text", "text": "POST 方法", "text_level": 1, "bbox": [ 147, 873, 263, 894 ], "page_idx": 23 }, { "type": "text", "text": "上面我们使用了GET 方法，视图显示和请求处理分成两个函数处理。", "bbox": [ 146, 95, 502, 105 ], "page_idx": 24 }, { "type": "text", "text": "提交数据时更常用POST 方法。我们下面使用该方法，并用一个URL和处理函数，同时显示视图和处理请求。", "bbox": [ 144, 112, 715, 124 ], "page_idx": 24 }, { "type": "text", "text": "1. GET 方法实现（search.py）", "text_level": 1, "bbox": [ 147, 131, 309, 143 ], "page_idx": 24 }, { "type": "text", "text": "python ", "bbox": [ 147, 151, 189, 162 ], "page_idx": 24 }, { "type": "text", "text": "# 两个独立的函数： 一个显示表单， 一个处理请求", "bbox": [ 146, 168, 411, 181 ], "page_idx": 24 }, { "type": "text", "text": "def search_form(request): # 显示表单 ", "bbox": [ 147, 187, 359, 199 ], "page_idx": 24 }, { "type": "text", "text": "return render(request, 'search_form.html') ", "bbox": [ 159, 206, 396, 218 ], "page_idx": 24 }, { "type": "text", "text": "def search(request): # 处理请求", "bbox": [ 147, 243, 327, 255 ], "page_idx": 24 }, { "type": "text", "text": "if 'q' in request.GET and request.GET['q']: ", "bbox": [ 159, 261, 384, 273 ], "page_idx": 24 }, { "type": "text", "text": "message $=$ '你搜索的内容为: ' $^ +$ request.GET['q'] ", "bbox": [ 171, 280, 431, 292 ], "page_idx": 24 }, { "type": "text", "text": "else: ", "bbox": [ 159, 299, 189, 309 ], "page_idx": 24 }, { "type": "text", "text": "message $=$ '你提交了空表单' ", "bbox": [ 171, 317, 324, 328 ], "page_idx": 24 }, { "type": "text", "text": "return HttpResponse(message)", "bbox": [ 159, 336, 336, 347 ], "page_idx": 24 }, { "type": "text", "text": "2. POST 方法实现（search2.py）", "text_level": 1, "bbox": [ 147, 355, 322, 367 ], "page_idx": 24 }, { "type": "text", "text": "python ", "bbox": [ 147, 373, 189, 384 ], "page_idx": 24 }, { "type": "text", "text": "# 单个函数同时处理表单显示和请求处理", "bbox": [ 147, 391, 364, 401 ], "page_idx": 24 }, { "type": "text", "text": "def search_post(request): ", "bbox": [ 147, 410, 290, 420 ], "page_idx": 24 }, { "type": "text", "text": "$\\mathsf { c t x } = \\left\\{ \\right\\}$ ", "bbox": [ 159, 429, 201, 439 ], "page_idx": 24 }, { "type": "text", "text": "if request.POST: # 如果是POST 请求 （表单提交）", "bbox": [ 159, 447, 423, 458 ], "page_idx": 24 }, { "type": "text", "text": "ctx['rlt'] $=$ request.POST['q'] ", "bbox": [ 171, 466, 322, 476 ], "page_idx": 24 }, { "type": "text", "text": "return render(request, \"post.html\", ctx) # 总是返回模板", "bbox": [ 159, 483, 468, 495 ], "page_idx": 24 }, { "type": "text", "text": "何时用 GET？何时用 POST？", "text_level": 1, "bbox": [ 147, 502, 297, 514 ], "page_idx": 24 }, { "type": "text", "text": "适合 GET 的情况：", "text_level": 1, "bbox": [ 147, 521, 243, 532 ], "page_idx": 24 }, { "type": "list", "sub_type": "text", "list_items": [ "搜索功能（用户可能想收藏或分享搜索结果URL）", ". 筛选和排序（参数在URL中便于分享）", "幂等操作（不改变服务器状态的操作）" ], "bbox": [ 176, 539, 463, 588 ], "page_idx": 24 }, { "type": "text", "text": "适合 POST 的情况：", "text_level": 1, "bbox": [ 147, 595, 250, 606 ], "page_idx": 24 }, { "type": "list", "sub_type": "text", "list_items": [ "登录/注册（包含敏感信息）", ". 表单提交（创建新数据）", ". 任何会改变服务器状态的操作", ". 大量数据提交 " ], "bbox": [ 176, 614, 364, 680 ], "page_idx": 24 }, { "type": "text", "text": "最佳实践总结", "text_level": 1, "bbox": [ 147, 688, 221, 699 ], "page_idx": 24 }, { "type": "list", "sub_type": "text", "list_items": [ "1. GET 完全可以用单函数处理显示和处理逻辑", "2. 原代码设计是过时的模式，现代 Django 开发不推荐这样分离", "3. 选择GET 还是 POST 取决于具体场景，而不是技术限制", "4. 单函数模式更简洁、更易维护" ], "bbox": [ 176, 706, 526, 772 ], "page_idx": 24 }, { "type": "text", "text": "Request 对象", "text_level": 1, "bbox": [ 147, 808, 294, 828 ], "page_idx": 24 }, { "type": "text", "text": "每个视图函数的第一个参数是一个HttpRequest 对象，就像下面这个runoob() 函数:", "bbox": [ 146, 841, 579, 854 ], "page_idx": 24 }, { "type": "text", "text": "from django.http import HttpResponse ", "bbox": [ 147, 860, 349, 872 ], "page_idx": 24 }, { "type": "text", "text": "QueryDict 对象", "text_level": 1, "bbox": [ 147, 102, 315, 122 ], "page_idx": 25 }, { "type": "text", "text": "在 HttpRequest 对象中, GET 和 POST 属性是 django.http.QueryDict 类的实例。QueryDict类似字典的自定义类，用来处理单键对应多值的情况。QueryDict实现所有标准的词典方法。还包括一些特有的方法：", "bbox": [ 144, 135, 554, 184 ], "page_idx": 25 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "def runoob(request): return HttpResponse(\"Hello world\")", "guess_lang": "python", "bbox": [ 146, 209, 347, 239 ], "page_idx": 25 }, { "type": "text", "text": "Django 视图", "text_level": 1, "bbox": [ 147, 259, 386, 293 ], "page_idx": 25 }, { "type": "text", "text": "视图层 ", "text_level": 1, "bbox": [ 147, 312, 240, 335 ], "page_idx": 25 }, { "type": "text", "text": "一个视图函数，简称视图，是一个简单的Python 函数，它接受Web 请求并且返回Web 响应。", "bbox": [ 146, 347, 635, 359 ], "page_idx": 25 }, { "type": "text", "text": "响应可以是一个HTML 页面、一个404 错误页面、重定向页面、XML 文档、或者一张图片...", "bbox": [ 146, 366, 626, 376 ], "page_idx": 25 }, { "type": "text", "text": "无论视图本身包含什么逻辑，都要返回响应。代码写在哪里都可以，只要在Python 目录下面，一般放在项目的views.py 文件中。", "bbox": [ 146, 384, 811, 395 ], "page_idx": 25 }, { "type": "text", "text": "每个视图函数都负责返回一个HttpResponse 对象，对象中包含生成的响应。", "bbox": [ 146, 403, 542, 414 ], "page_idx": 25 }, { "type": "text", "text": "视图层中有两个重要的对象：请求对象(request)与响应对象(HttpResponse)。", "bbox": [ 146, 420, 544, 432 ], "page_idx": 25 }, { "type": "text", "text": "请求对象: HttpRequest 对象（简称 request 对象）", "bbox": [ 146, 439, 413, 451 ], "page_idx": 25 }, { "type": "text", "text": "以下介绍几个常用的request 属性。", "bbox": [ 146, 458, 329, 470 ], "page_idx": 25 }, { "type": "text", "text": "1、GET", "text_level": 1, "bbox": [ 147, 488, 228, 504 ], "page_idx": 25 }, { "type": "text", "text": "数据类型是QueryDict，一个类似于字典的对象，包含HTTP GET 的所有参数。", "bbox": [ 146, 520, 556, 531 ], "page_idx": 25 }, { "type": "text", "text": "有相同的键，就把所有的值放到对应的列表里。", "bbox": [ 146, 539, 391, 549 ], "page_idx": 25 }, { "type": "text", "text": "取值格式：对象.方法。", "bbox": [ 146, 557, 265, 568 ], "page_idx": 25 }, { "type": "text", "text": "get()：返回字符串，如果该键对应有多个值，取出该键的最后一个值。", "bbox": [ 146, 576, 509, 587 ], "page_idx": 25 }, { "type": "text", "text": "实例", "bbox": [ 147, 595, 174, 605 ], "page_idx": 25 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "def runoob(request):\n name = request.GET.get(\"name\")\n return HttpResponse('姓名：{}''.format(name)) ", "guess_lang": "python", "bbox": [ 146, 613, 405, 662 ], "page_idx": 25 }, { "type": "text", "text": "2、POST", "text_level": 1, "bbox": [ 146, 678, 245, 695 ], "page_idx": 25 }, { "type": "text", "text": "数据类型是QueryDict，一个类似于字典的对象，包含HTTP POST 的所有参数。", "bbox": [ 146, 711, 563, 722 ], "page_idx": 25 }, { "type": "text", "text": "常用于form 表单，form 表单里的标签name 属性对应参数的键，value 属性对应参数的值。", "bbox": [ 146, 730, 618, 741 ], "page_idx": 25 }, { "type": "text", "text": "取值格式：对象.方法。", "bbox": [ 146, 747, 267, 759 ], "page_idx": 25 }, { "type": "text", "text": "get()：返回字符串，如果该键对应有多个值，取出该键的最后一个值。", "bbox": [ 146, 766, 509, 778 ], "page_idx": 25 }, { "type": "text", "text": "实例", "bbox": [ 147, 785, 174, 796 ], "page_idx": 25 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "def runoob(request):\n name = request.POST.get(\"name\")\n return HttpResponse('姓名：{}'.format(name)) ", "guess_lang": "python", "bbox": [ 146, 804, 405, 853 ], "page_idx": 25 }, { "type": "text", "text": "3、body ", "text_level": 1, "bbox": [ 146, 870, 243, 889 ], "page_idx": 25 }, { "type": "text", "text": "数据类型是二进制字节流，是原生请求体里的参数内容，在HTTP 中用于POST，因为GET 没有请求体。", "bbox": [ 144, 95, 690, 107 ], "page_idx": 26 }, { "type": "text", "text": "在HTTP 中不常用，而在处理非HTTP 形式的报文时非常有用，例如：二进制图片、XML、Json 等。", "bbox": [ 144, 112, 670, 124 ], "page_idx": 26 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 131, 176, 143 ], "page_idx": 26 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "def runoob(request): name $=$ request.body print(name) return HttpResponse(\"菜鸟教程\") ", "bbox": [ 147, 151, 339, 219 ], "page_idx": 26 }, { "type": "text", "text": "获取URL 中的路径部分，数据类型是字符串。", "bbox": [ 146, 224, 384, 236 ], "page_idx": 26 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 243, 176, 255 ], "page_idx": 26 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "def runoob(request): name $=$ request.path print(name) return HttpResponse(\"菜鸟教程\") ", "bbox": [ 147, 262, 336, 330 ], "page_idx": 26 }, { "type": "text", "text": "4、path ", "text_level": 1, "bbox": [ 146, 346, 240, 365 ], "page_idx": 26 }, { "type": "text", "text": "获取URL 中的路径部分，数据类型是字符串。", "bbox": [ 146, 379, 384, 391 ], "page_idx": 26 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 397, 176, 409 ], "page_idx": 26 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "def runoob(request): name $=$ request.path print(name) return HttpResponse(\"菜鸟教程\") ", "bbox": [ 147, 414, 337, 483 ], "page_idx": 26 }, { "type": "text", "text": "5、method ", "text_level": 1, "bbox": [ 146, 519, 278, 536 ], "page_idx": 26 }, { "type": "text", "text": "获取当前请求的方式，数据类型是字符串，且结果为大写。", "bbox": [ 146, 551, 450, 563 ], "page_idx": 26 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 570, 176, 581 ], "page_idx": 26 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "def runoob(request): name $=$ request.method print(name) return HttpResponse(\"菜鸟教程\") ", "bbox": [ 147, 588, 339, 656 ], "page_idx": 26 }, { "type": "text", "text": "响应对象：HttpResponse 对象", "text_level": 1, "bbox": [ 146, 670, 584, 696 ], "page_idx": 26 }, { "type": "text", "text": "响应对象主要有三种形式：HttpResponse()、render()、redirect()。", "bbox": [ 146, 705, 492, 718 ], "page_idx": 26 }, { "type": "text", "text": "HttpResponse(): 返回文本，参数为字符串，字符串中写文本内容。如果参数为字符串里含有html 标签，也可以渲染。", "bbox": [ 144, 724, 759, 736 ], "page_idx": 26 }, { "type": "text", "text": "ender(): 返回文本，第一个参数为 request，第二个参数为字符串（页面名称），第三个参数为字典（可选参数，向页面传递的参数：", "bbox": [ 144, 741, 840, 753 ], "page_idx": 26 }, { "type": "text", "text": "键为页面参数名，值为views参数名）。", "bbox": [ 146, 760, 354, 772 ], "page_idx": 26 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 778, 176, 791 ], "page_idx": 26 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "def runoob(request):\n name = \"菜鸟教程\"\n return render(request, \"runoob.html\", {\"name\": name}) ", "guess_lang": "python", "bbox": [ 147, 797, 438, 847 ], "page_idx": 26 }, { "type": "text", "text": "redirect()：重定向，跳转新页面。参数为字符串，字符串中填写页面路径。一般用于form 表单提交后，跳转到新页面。", "bbox": [ 146, 854, 766, 866 ], "page_idx": 26 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 872, 176, 884 ], "page_idx": 26 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "def runoob(request): ", "guess_lang": "txt", "bbox": [ 147, 891, 260, 903 ], "page_idx": 26 }, { "type": "text", "text": "return redirect(\"/index/\") ", "bbox": [ 159, 96, 290, 105 ], "page_idx": 27 }, { "type": "text", "text": "render 和 redirect 是在 HttpResponse 的基础上进行了封装：", "bbox": [ 146, 112, 460, 124 ], "page_idx": 27 }, { "type": "list", "sub_type": "text", "list_items": [ "render：底层返回的也是 HttpResponse 对象", "redirect：底层继承的是 HttpResponse 对象" ], "bbox": [ 176, 131, 443, 162 ], "page_idx": 27 }, { "type": "text", "text": "Django 路由", "text_level": 1, "bbox": [ 149, 183, 384, 217 ], "page_idx": 27 }, { "type": "text", "text": "路由简单的来说就是根据用户请求的URL 链接来判断对应的处理程序，并返回处理结果，也就是URL 与Django 的视图建立映射关系。", "bbox": [ 144, 230, 845, 243 ], "page_idx": 27 }, { "type": "text", "text": "Django 路由在 urls.py 配置，urls.py 中的每一条配置对应相应的处理方法。", "bbox": [ 146, 249, 534, 261 ], "page_idx": 27 }, { "type": "text", "text": "Path 设置 ", "text_level": 1, "bbox": [ 147, 275, 287, 298 ], "page_idx": 27 }, { "type": "text", "text": "Django 2.2.x 之后的版本", "text_level": 1, "bbox": [ 146, 311, 282, 322 ], "page_idx": 27 }, { "type": "list", "sub_type": "text", "list_items": [ "path：用于普通路径，不需要自己手动添加正则首位限制符号，底层已经添加。", ". re_path：用于正则路径，需要自己手动添加正则首位限制符号。" ], "bbox": [ 176, 329, 616, 359 ], "page_idx": 27 }, { "type": "text", "text": "实例", "bbox": [ 146, 366, 174, 376 ], "page_idx": 27 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "from django.url import re_path # 用re_path 需要引入\nurlpatterns = [\n path('admin/', admin.site URLs),\n path('index/', views.index), # 普通路径\n re_path(r'^articles/[0-9]{4}]/$', views_articles), # 正则路径 ", "guess_lang": "python", "bbox": [ 144, 384, 465, 489 ], "page_idx": 27 }, { "type": "text", "text": "正则路径中的分组", "text_level": 1, "bbox": [ 147, 502, 394, 526 ], "page_idx": 27 }, { "type": "text", "text": "正则路径中的无名分组", "text_level": 1, "bbox": [ 147, 544, 378, 563 ], "page_idx": 27 }, { "type": "text", "text": "无名分组按位置传参，一一对应。", "bbox": [ 146, 577, 322, 590 ], "page_idx": 27 }, { "type": "text", "text": "views 中除了request，其他形参的数量要与urls 中的分组数量一致。", "bbox": [ 146, 596, 502, 609 ], "page_idx": 27 }, { "type": "text", "text": "urls.py ", "bbox": [ 146, 615, 189, 627 ], "page_idx": 27 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "urlpatterns $=$ [ path('admin'/,admin.site URLs), re_path(\"^index/([0-9]{4})/$\",views.index), ] views.py from django.shortcuts import HttpResponse ", "bbox": [ 146, 634, 384, 739 ], "page_idx": 27 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "def index(request, year):\n print(year) # 一个形参代表路径中一个分组的内容，按顺序匹配\n return HttpResponse('菜鸟教程')", "guess_lang": "python", "bbox": [ 146, 764, 494, 813 ], "page_idx": 27 }, { "type": "text", "text": "正则路径中的有名分组", "text_level": 1, "bbox": [ 147, 828, 379, 847 ], "page_idx": 27 }, { "type": "text", "text": "语法：", "bbox": [ 147, 862, 181, 873 ], "page_idx": 27 }, { "type": "text", "text": "(?P<组名>正则表达式) ", "bbox": [ 147, 881, 270, 892 ], "page_idx": 27 }, { "type": "text", "text": "有名分组按关键字传参，与位置顺序无关。", "bbox": [ 144, 95, 366, 105 ], "page_idx": 28 }, { "type": "text", "text": "views 中除了request，其他形参的数量要与urls 中的分组数量一致，并且views 中的形参名称要与urls 中的组名对应。", "bbox": [ 144, 112, 764, 124 ], "page_idx": 28 }, { "type": "text", "text": "urls.py ", "bbox": [ 146, 131, 189, 143 ], "page_idx": 28 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "urlpatterns $=$ [path('admin／',admin.site.urls),re_path(\"^index/(?P[0-9]{4})/(?P[0-9]{2})/\\$\"，views.index),]views.pyfrom django.shortcuts import HttpResponsedef index(request, year, month):print(year,month)#一个形参代表路径中一个分组的内容,return HttpResponse('菜鸟教程') ", "bbox": [ 146, 151, 463, 312 ], "page_idx": 28 }, { "type": "text", "text": "路由分发(include) ", "text_level": 1, "bbox": [ 146, 326, 339, 346 ], "page_idx": 28 }, { "type": "text", "text": "存在问题：Django 项目里多个app目录共用一个urls 容易造成混淆，后期维护也不方便。", "bbox": [ 144, 360, 608, 372 ], "page_idx": 28 }, { "type": "text", "text": "解决：使用路由分发（include），让每个app目录都单独拥有自己的urls。", "bbox": [ 144, 379, 532, 390 ], "page_idx": 28 }, { "type": "text", "text": "步骤：", "bbox": [ 146, 397, 179, 407 ], "page_idx": 28 }, { "type": "list", "sub_type": "text", "list_items": [ "1、在每个 app 目录里都创建一个 urls.py 文件。", "2、在项目名称目录下的urls 文件里，统一将路径分发给各个app 目录。" ], "bbox": [ 176, 416, 578, 445 ], "page_idx": 28 }, { "type": "text", "text": "实例", "bbox": [ 146, 451, 174, 464 ], "page_idx": 28 }, { "type": "text", "text": "from django.contrib import admin ", "bbox": [ 144, 470, 329, 482 ], "page_idx": 28 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "from django.url import path, include # 从 django.url 引入 include \nurlpatterns = [ \n path('admin/', admin.site URLs), \n path(\"app01/\", include(\"app01 URLs\")), \n path(\"app02/\", include(\"app02 URLs\")), ", "guess_lang": "python", "bbox": [ 144, 489, 495, 575 ], "page_idx": 28 }, { "type": "text", "text": "反向解析", "text_level": 1, "bbox": [ 147, 608, 272, 631 ], "page_idx": 28 }, { "type": "text", "text": "随着功能的增加，路由层的url 发生变化，就需要去更改对应的视图层和模板层的url，非常麻烦，不便维护。", "bbox": [ 144, 644, 707, 655 ], "page_idx": 28 }, { "type": "text", "text": "这时我们可以利用反向解析，当路由层url 发生改变，在视图层和模板层动态反向解析出更改后的url，免去修改的操作。", "bbox": [ 144, 662, 766, 673 ], "page_idx": 28 }, { "type": "text", "text": "反向解析一般用在模板中的超链接及视图中的重定向。", "bbox": [ 146, 681, 426, 692 ], "page_idx": 28 }, { "type": "text", "text": "普通路径", "text_level": 1, "bbox": [ 147, 709, 240, 727 ], "page_idx": 28 }, { "type": "text", "text": "在urls.py 中给路由起别名，name=\"路由别名\"。", "bbox": [ 144, 741, 396, 753 ], "page_idx": 28 }, { "type": "text", "text": "path(\"login1/\", views.login, name=\"login\") ", "bbox": [ 146, 760, 364, 772 ], "page_idx": 28 }, { "type": "text", "text": "在 views.py 中，从 django.urls 中引入 reverse，利用 reverse(\"路由别名\") 反向解析:", "bbox": [ 146, 778, 588, 791 ], "page_idx": 28 }, { "type": "text", "text": "return redirect(reverse(\"login\")) ", "bbox": [ 146, 797, 312, 809 ], "page_idx": 28 }, { "type": "text", "text": "在模板 templates 中的 HTML 文件中，利用 {% url \"路由别名\" %} 反向解析。", "bbox": [ 144, 816, 544, 828 ], "page_idx": 28 }, { "type": "text", "text": "
", "bbox": [ 146, 835, 400, 846 ], "page_idx": 28 }, { "type": "text", "text": "正则路径（无名分组）", "text_level": 1, "bbox": [ 146, 863, 364, 882 ], "page_idx": 28 }, { "type": "text", "text": "在 urls.py 中给路由起别名，name=\"路由别名\"。", "bbox": [ 144, 95, 400, 107 ], "page_idx": 29 }, { "type": "text", "text": "re_path(r\"^login/([0-9]{2})/$\", views.login, name=\"login\") ", "bbox": [ 144, 112, 440, 124 ], "page_idx": 29 }, { "type": "text", "text": "在 views.py 中，从 django.urls 中引入 reverse，利用 reverse(\"路由别名\"，args=(符合正则匹配的参数,)) 反向解析。", "bbox": [ 144, 131, 751, 143 ], "page_idx": 29 }, { "type": "text", "text": "return redirect(reverse(\"login\",args=(10,))) ", "bbox": [ 144, 151, 369, 162 ], "page_idx": 29 }, { "type": "text", "text": "在模板 templates 中的 HTML 文件中利用 {% url \"路由别名\" 符合正则匹配的参数 %} 反向解析。", "bbox": [ 144, 168, 642, 181 ], "page_idx": 29 }, { "type": "text", "text": " ", "bbox": [ 144, 187, 416, 199 ], "page_idx": 29 }, { "type": "text", "text": "正则路径（有名分组）", "text_level": 1, "bbox": [ 146, 215, 366, 234 ], "page_idx": 29 }, { "type": "text", "text": "在 urls.py 中给路由起别名，name=\"路由别名\"。", "bbox": [ 144, 249, 400, 261 ], "page_idx": 29 }, { "type": "text", "text": "re_path(r\"^login/(?P[0-9]{4})/$\", views.login, name=\"login\") ", "bbox": [ 144, 267, 490, 279 ], "page_idx": 29 }, { "type": "text", "text": "在 views.py 中，从 django.urls 中引入 reverse，利用 reverse(\"路由别名\"，kwargs={\"分组名\":符合正则匹配的参数}) 反向解析。", "bbox": [ 144, 286, 813, 298 ], "page_idx": 29 }, { "type": "text", "text": "return redirect(reverse(\"login\",kwargs={\"year\":3333})) ", "bbox": [ 146, 304, 428, 316 ], "page_idx": 29 }, { "type": "text", "text": "在模板 templates 中的 HTML 文件中，利用{% url \"路由别名\" 分组名=符合正则匹配的参数 %} 反向解析。", "bbox": [ 144, 323, 695, 335 ], "page_idx": 29 }, { "type": "text", "text": " ", "bbox": [ 144, 342, 458, 353 ], "page_idx": 29 }, { "type": "text", "text": "命名空间", "text_level": 1, "bbox": [ 146, 386, 273, 409 ], "page_idx": 29 }, { "type": "text", "text": "命名空间（英语：Namespace）是表示标识符的可见范围。", "bbox": [ 144, 420, 455, 432 ], "page_idx": 29 }, { "type": "text", "text": "一个标识符可在多个命名空间中定义，它在不同命名空间中的含义是互不相干的。", "bbox": [ 144, 439, 569, 451 ], "page_idx": 29 }, { "type": "text", "text": "一个新的命名空间中可定义任何标识符，它们不会与任何重复的标识符发生冲突，因为重复的定义都处于其它命名空间中。", "bbox": [ 144, 458, 779, 469 ], "page_idx": 29 }, { "type": "text", "text": "存在问题：路由别名 name 没有作用域，Django 在反向解析 URL 时，会在项目全局顺序搜索，当查找到第一个路由别名 name 指定", "bbox": [ 144, 476, 848, 488 ], "page_idx": 29 }, { "type": "text", "text": "URL 时，立即返回。当在不同的 app 目录下的 urls 中定义相同的路由别名 name 时，可能会导致 URL 反向解析错误。", "bbox": [ 144, 495, 756, 507 ], "page_idx": 29 }, { "type": "text", "text": "解决：使用命名空间。", "bbox": [ 144, 514, 262, 526 ], "page_idx": 29 }, { "type": "text", "text": "普通路径", "text_level": 1, "bbox": [ 146, 533, 200, 544 ], "page_idx": 29 }, { "type": "text", "text": "定义命名空间（include 里面是一个元组）格式如下：", "bbox": [ 144, 551, 420, 562 ], "page_idx": 29 }, { "type": "text", "text": "include((\"app 名称：urls\"，\"app 名称\"))", "bbox": [ 144, 570, 354, 582 ], "page_idx": 29 }, { "type": "text", "text": "实例：", "bbox": [ 146, 588, 179, 599 ], "page_idx": 29 }, { "type": "text", "text": "path(\"app01/\", include((\"app01.urls\",\"app01\"))) ", "bbox": [ 144, 606, 393, 618 ], "page_idx": 29 }, { "type": "text", "text": "path(\"app02/\", include((\"app02.urls\",\"app02\"))) ", "bbox": [ 144, 625, 393, 637 ], "page_idx": 29 }, { "type": "text", "text": "在 app01/urls.py 中起相同的路由别名。", "bbox": [ 144, 644, 349, 655 ], "page_idx": 29 }, { "type": "text", "text": "path(\"login/\", views.login, name=\"login\") ", "bbox": [ 144, 662, 357, 674 ], "page_idx": 29 }, { "type": "text", "text": "在views.py 中使用名称空间，语法格式如下：", "bbox": [ 144, 681, 383, 692 ], "page_idx": 29 }, { "type": "text", "text": "reverse(\"app 名称：路由别名\")", "bbox": [ 144, 699, 310, 711 ], "page_idx": 29 }, { "type": "text", "text": "实例：", "bbox": [ 146, 718, 179, 728 ], "page_idx": 29 }, { "type": "text", "text": "return redirect(reverse(\"app01:login\") ", "bbox": [ 144, 737, 344, 747 ], "page_idx": 29 }, { "type": "text", "text": "Django Admin 管理工具", "text_level": 1, "bbox": [ 147, 768, 610, 802 ], "page_idx": 29 }, { "type": "text", "text": "Django 提供了基于web 的管理工具。", "text_level": 1, "bbox": [ 146, 822, 532, 843 ], "page_idx": 29 }, { "type": "text", "text": "Django 自动管理工具是 django.contrib 的一部分。你可以在项目的 settings.py 中的 INSTALLED_APPS 看到它：", "bbox": [ 144, 856, 727, 869 ], "page_idx": 29 }, { "type": "text", "text": "/HelloWorld/HelloWorld/settings.py 文件代码：", "bbox": [ 144, 875, 386, 887 ], "page_idx": 29 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "INSTALLED_APPS = ( ", "guess_lang": "txt", "bbox": [ 147, 95, 270, 105 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "'django.contrib_admin', ", "guess_lang": "txt", "bbox": [ 161, 114, 280, 124 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "'django.contrib.auth', ", "guess_lang": "txt", "bbox": [ 161, 131, 272, 143 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "'django.contrib.contenttypes', ", "guess_lang": "python", "bbox": [ 161, 151, 315, 162 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "'django.contrib.authenticated', ", "guess_lang": "javascript", "bbox": [ 161, 168, 295, 180 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "'django.contrib.messages', ", "guess_lang": "javascript", "bbox": [ 161, 187, 302, 199 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "'django.contrib(staticfiles',", "guess_lang": "javascript", "bbox": [ 161, 206, 297, 217 ], "page_idx": 30 }, { "type": "text", "text": ")django.contrib 是一套庞大的功能集，它是 Django 基本代码的组成部分。", "bbox": [ 146, 224, 524, 236 ], "page_idx": 30 }, { "type": "text", "text": "激活管理工具", "text_level": 1, "bbox": [ 147, 252, 287, 271 ], "page_idx": 30 }, { "type": "text", "text": "通常我们在生成项目时会在urls.py 中自动设置好，我们只需去掉注释即可。", "bbox": [ 146, 286, 537, 298 ], "page_idx": 30 }, { "type": "text", "text": "配置项如下所示：", "bbox": [ 147, 304, 238, 316 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "/HelloWorld/HelloWorld/url.py文件代码：", "guess_lang": "txt", "bbox": [ 146, 323, 366, 335 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "urls.py ", "guess_lang": "txt", "bbox": [ 147, 342, 196, 353 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "from django.conf.urls import url ", "guess_lang": "python", "bbox": [ 147, 360, 312, 370 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "from django.contrib import admin ", "guess_lang": "python", "bbox": [ 147, 378, 322, 390 ], "page_idx": 30 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "urlpatterns $=$ [ ", "bbox": [ 147, 397, 223, 409 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "url(r'^admin\"', admin.site.url), ", "guess_lang": "javascript", "bbox": [ 161, 414, 319, 426 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "] ", "guess_lang": "txt", "bbox": [ 147, 435, 156, 445 ], "page_idx": 30 }, { "type": "text", "text": "当这一切都配置好后，Django 管理工具就可以运行了。", "bbox": [ 147, 451, 431, 464 ], "page_idx": 30 }, { "type": "text", "text": "你可以通过命令 python manage.py createsuperuser 来创建超级用户，如下所示：", "bbox": [ 146, 470, 584, 483 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "python manage.py createsuperuser ", "guess_lang": "batch", "bbox": [ 147, 489, 347, 502 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "Username (leave blank to use 'root'): admin ", "guess_lang": "txt", "bbox": [ 147, 508, 376, 520 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "Email address: admin@runoob.com ", "guess_lang": "txt", "bbox": [ 147, 527, 337, 538 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "Password: ", "guess_lang": "txt", "bbox": [ 147, 546, 205, 556 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "Password (again): ", "guess_lang": "txt", "bbox": [ 147, 564, 245, 576 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "Superuser created successfully. ", "guess_lang": "txt", "bbox": [ 147, 582, 317, 594 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "[root@solar HelloWorld]# ", "guess_lang": "txt", "bbox": [ 147, 601, 282, 613 ], "page_idx": 30 }, { "type": "text", "text": "复杂模型", "text_level": 1, "bbox": [ 147, 629, 242, 646 ], "page_idx": 30 }, { "type": "text", "text": "管理页面的功能强大，完全有能力处理更加复杂的数据模型。", "bbox": [ 146, 662, 462, 674 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "django-admin.py startproject app01 ", "guess_lang": "txt", "bbox": [ 147, 681, 336, 693 ], "page_idx": 30 }, { "type": "text", "text": "接下来在 settings.py 中找到 INSTALLED_APPS 这一项，如下：", "bbox": [ 147, 699, 478, 711 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "INSTALLED_APPS = ( ", "guess_lang": "txt", "bbox": [ 147, 718, 270, 728 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "'django.contrib_admin', ", "guess_lang": "txt", "bbox": [ 161, 737, 280, 747 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "'django.contrib.auth', ", "guess_lang": "txt", "bbox": [ 161, 755, 272, 766 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "'django.contrib.contenttypes', ", "guess_lang": "python", "bbox": [ 161, 772, 315, 785 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "'django.contribsessions', ", "guess_lang": "javascript", "bbox": [ 161, 791, 295, 804 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "'django.contrib.messages', ", "guess_lang": "javascript", "bbox": [ 161, 810, 302, 822 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "'django.contrib(staticfiles',", "guess_lang": "javascript", "bbox": [ 161, 829, 297, 840 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "'testmodel', # 添加此项 ", "guess_lang": "txt", "bbox": [ 161, 847, 329, 859 ], "page_idx": 30 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "）", "guess_lang": "txt", "bbox": [ 147, 866, 156, 878 ], "page_idx": 30 }, { "type": "text", "text": "建表", "text_level": 1, "bbox": [ 147, 101, 200, 120 ], "page_idx": 31 }, { "type": "text", "text": "先在 TestModel/models.py 中增加一个更复杂的数据模型：", "bbox": [ 147, 162, 450, 175 ], "page_idx": 31 }, { "type": "text", "text": "HelloWorld/TestModel/models.py: 文件代码：", "bbox": [ 147, 181, 381, 193 ], "page_idx": 31 }, { "type": "text", "text": "from django.db import models ", "bbox": [ 147, 199, 307, 212 ], "page_idx": 31 }, { "type": "text", "text": "# Create your models here. ", "bbox": [ 147, 237, 295, 249 ], "page_idx": 31 }, { "type": "text", "text": "class Test(models.Model): ", "bbox": [ 147, 255, 287, 267 ], "page_idx": 31 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "name = models.CharField(max_length=20) ", "guess_lang": "python", "bbox": [ 161, 273, 388, 286 ], "page_idx": 31 }, { "type": "text", "text": "class Contact(models.Model): ", "bbox": [ 147, 311, 307, 323 ], "page_idx": 31 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "name $=$ models.CharField(max_length=200) ", "bbox": [ 161, 329, 401, 341 ], "page_idx": 31 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "age $=$ models.IntegerField(default=0) ", "bbox": [ 161, 348, 366, 360 ], "page_idx": 31 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "email = models.EmailField() ", "guess_lang": "txt", "bbox": [ 161, 367, 312, 378 ], "page_idx": 31 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "def __unicode__(self): ", "guess_lang": "python", "bbox": [ 161, 385, 280, 397 ], "page_idx": 31 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "return self.name ", "guess_lang": "lua", "bbox": [ 173, 404, 263, 414 ], "page_idx": 31 }, { "type": "text", "text": "class Tag(models.Model): ", "bbox": [ 147, 439, 285, 451 ], "page_idx": 31 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "contact = models.FireignKey(Contact, on_delete=models.CASCADE,) ", "guess_lang": "python", "bbox": [ 161, 458, 531, 470 ], "page_idx": 31 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "name $=$ models.CharField(max_length=50) ", "bbox": [ 161, 478, 396, 489 ], "page_idx": 31 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "def __unicode__(self): ", "guess_lang": "python", "bbox": [ 161, 495, 280, 508 ], "page_idx": 31 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "return self.name ", "guess_lang": "lua", "bbox": [ 173, 514, 263, 525 ], "page_idx": 31 }, { "type": "text", "text": "这里有两个表。Tag 以 Contact 为外部键。一个 Contact 可以对应多个 Tag。", "bbox": [ 147, 533, 539, 546 ], "page_idx": 31 }, { "type": "text", "text": "我们还可以看到许多在之前没有见过的属性类型，比如 IntegerField 用于存储整数。", "bbox": [ 146, 570, 578, 583 ], "page_idx": 31 }, { "type": "text", "text": "用 django 创建表", "text_level": 1, "bbox": [ 147, 611, 337, 633 ], "page_idx": 31 }, { "type": "text", "text": "$ python manage.py migrate # 创建表结构", "bbox": [ 146, 674, 379, 686 ], "page_idx": 31 }, { "type": "text", "text": "python manage.py makemigrations testmodel 让模型知道我们的表有变更", "bbox": [ 146, 692, 536, 703 ], "page_idx": 31 }, { "type": "text", "text": "python manage.py migrate TestModel 创建表结构", "bbox": [ 147, 709, 408, 722 ], "page_idx": 31 }, { "type": "text", "text": "接下来我们在 app01 项目里添加 views.py 和 models.py 文件，app01 项目目录结构：", "bbox": [ 146, 728, 586, 741 ], "page_idx": 31 }, { "type": "text", "text": "app01 ", "bbox": [ 147, 747, 184, 759 ], "page_idx": 31 }, { "type": "text", "text": "|-- app01 ", "bbox": [ 147, 766, 196, 777 ], "page_idx": 31 }, { "type": "text", "text": "| |-- __init__.py", "bbox": [ 147, 785, 236, 797 ], "page_idx": 31 }, { "type": "text", "text": "| |-- __pycache__", "bbox": [ 147, 803, 248, 815 ], "page_idx": 31 }, { "type": "text", "text": "| |-- asgi.py ", "bbox": [ 147, 822, 216, 833 ], "page_idx": 31 }, { "type": "text", "text": "| |-- migrations ", "bbox": [ 147, 840, 233, 852 ], "page_idx": 31 }, { "type": "text", "text": "| |-- models.py", "bbox": [ 147, 859, 233, 870 ], "page_idx": 31 }, { "type": "text", "text": "| |-- settings.py", "bbox": [ 147, 877, 235, 889 ], "page_idx": 31 }, { "type": "list", "sub_type": "text", "list_items": [ "| |-- urls.py", "| |-- views.py", "| `-- wsgi.py" ], "bbox": [ 146, 95, 223, 143 ], "page_idx": 32 }, { "type": "text", "text": "显示模型", "text_level": 1, "bbox": [ 147, 192, 245, 211 ], "page_idx": 32 }, { "type": "text", "text": "在 TestModel/admin.py 注册多个模型并显示：", "bbox": [ 146, 252, 490, 268 ], "page_idx": 32 }, { "type": "text", "text": "HelloWorld/TestModel/admin.py: 文件代码：", "bbox": [ 146, 290, 376, 302 ], "page_idx": 32 }, { "type": "text", "text": "from django.contrib import admin ", "bbox": [ 146, 309, 322, 319 ], "page_idx": 32 }, { "type": "text", "text": "from TestModel.models import Test,Contact,Tag ", "bbox": [ 146, 328, 400, 338 ], "page_idx": 32 }, { "type": "text", "text": "# Register your models here. ", "bbox": [ 146, 365, 302, 376 ], "page_idx": 32 }, { "type": "text", "text": "admin.site.register([Test, Contact, Tag]) ", "bbox": [ 146, 382, 354, 395 ], "page_idx": 32 }, { "type": "text", "text": "每个栏也可以定义自己的格式。", "text_level": 1, "bbox": [ 146, 424, 465, 444 ], "page_idx": 32 }, { "type": "text", "text": "修改 TestModel/admin.py 为：", "bbox": [ 146, 486, 302, 498 ], "page_idx": 32 }, { "type": "text", "text": "HelloWorld/TestModel/admin.py: 文件代码：", "bbox": [ 146, 523, 374, 535 ], "page_idx": 32 }, { "type": "text", "text": "from django.contrib import admin ", "bbox": [ 146, 542, 322, 552 ], "page_idx": 32 }, { "type": "text", "text": "from TestModel.models import Test,Contact,Tag ", "bbox": [ 146, 560, 400, 571 ], "page_idx": 32 }, { "type": "text", "text": "# Register your models here. ", "bbox": [ 146, 596, 302, 608 ], "page_idx": 32 }, { "type": "text", "text": "class ContactAdmin(admin.ModelAdmin): ", "bbox": [ 146, 615, 366, 627 ], "page_idx": 32 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "fieldsets = (\n ['Main', {\n 'fields': ('name', 'email'),\n }],\n ['Advance', {\n 'classes': ('collapse'), # CSS\n 'fields': ('age'), }\n }]) ", "guess_lang": "python", "bbox": [ 146, 634, 341, 793 ], "page_idx": 32 }, { "type": "text", "text": "admin.site.register(Contact, ContactAdmin) ", "bbox": [ 146, 820, 376, 831 ], "page_idx": 32 }, { "type": "text", "text": "admin.site.register([Test, Tag]) ", "bbox": [ 146, 838, 309, 848 ], "page_idx": 32 }, { "type": "text", "text": "上面的栏目分为了Main 和Advance 两部分。classes 说明它所在的部分的CSS 格式。这里让Advance 部分隐藏：", "bbox": [ 146, 856, 739, 868 ], "page_idx": 32 }, { "type": "text", "text": "内联(Inline)显示", "text_level": 1, "bbox": [ 147, 101, 329, 122 ], "page_idx": 33 }, { "type": "text", "text": "上面的Contact 是Tag 的外部键，所以有外部参考的关系。", "bbox": [ 146, 162, 450, 174 ], "page_idx": 33 }, { "type": "text", "text": "而在默认的页面显示中，将两者分离开来，无法体现出两者的从属关系。我们可以使用内联显示，让 Tag 附加在Contact 的编辑页面上显示。", "bbox": [ 144, 181, 847, 210 ], "page_idx": 33 }, { "type": "text", "text": "修改 TestModel/admin.py：", "bbox": [ 146, 219, 285, 229 ], "page_idx": 33 }, { "type": "text", "text": "HelloWorld/TestModel/admin.py: 文件代码：", "bbox": [ 146, 237, 386, 248 ], "page_idx": 33 }, { "type": "text", "text": "from django.contrib import admin ", "bbox": [ 146, 255, 322, 265 ], "page_idx": 33 }, { "type": "text", "text": "from TestModel.models import Test,Contact,Tag ", "bbox": [ 146, 274, 400, 284 ], "page_idx": 33 }, { "type": "text", "text": "# Register your models here. ", "bbox": [ 146, 311, 300, 321 ], "page_idx": 33 }, { "type": "text", "text": "class TagInline(admin.TabularInline): ", "bbox": [ 146, 329, 339, 338 ], "page_idx": 33 }, { "type": "text", "text": "model = Tag ", "bbox": [ 161, 349, 226, 359 ], "page_idx": 33 }, { "type": "text", "text": "class ContactAdmin(admin.ModelAdmin): ", "bbox": [ 146, 385, 366, 395 ], "page_idx": 33 }, { "type": "text", "text": "inlines $=$ [TagInline] # Inline ", "bbox": [ 161, 404, 307, 414 ], "page_idx": 33 }, { "type": "text", "text": "fieldsets = ( ", "bbox": [ 161, 422, 225, 432 ], "page_idx": 33 }, { "type": "text", "text": "['Main',{ ", "bbox": [ 174, 441, 216, 451 ], "page_idx": 33 }, { "type": "text", "text": "'fields':('name','email'), ", "bbox": [ 186, 460, 305, 470 ], "page_idx": 33 }, { "type": "text", "text": "}], ", "bbox": [ 174, 479, 184, 488 ], "page_idx": 33 }, { "type": "text", "text": "['Advance',{ ", "bbox": [ 174, 495, 236, 506 ], "page_idx": 33 }, { "type": "text", "text": "'classes': ('collapse',), ", "bbox": [ 186, 514, 300, 526 ], "page_idx": 33 }, { "type": "text", "text": "'fields': ('age',), ", "bbox": [ 188, 533, 267, 544 ], "page_idx": 33 }, { "type": "text", "text": "}] ", "bbox": [ 174, 552, 184, 562 ], "page_idx": 33 }, { "type": "text", "text": ") ", "bbox": [ 157, 589, 168, 599 ], "page_idx": 33 }, { "type": "text", "text": "admin.site.register(Contact, ContactAdmin) ", "bbox": [ 146, 626, 374, 637 ], "page_idx": 33 }, { "type": "text", "text": "admin.site.register([Test]) ", "bbox": [ 147, 645, 282, 655 ], "page_idx": 33 }, { "type": "text", "text": "自定义该页面的显示", "text_level": 1, "bbox": [ 147, 686, 363, 705 ], "page_idx": 33 }, { "type": "text", "text": "比如在列表中显示更多的栏目，只需要在 ContactAdmin 中增加 list_display 属性:", "bbox": [ 146, 747, 568, 759 ], "page_idx": 33 }, { "type": "text", "text": "HelloWorld/TestModel/admin.py: 文件代码：", "bbox": [ 146, 785, 374, 795 ], "page_idx": 33 }, { "type": "text", "text": "from django.contrib import admin ", "bbox": [ 146, 804, 322, 813 ], "page_idx": 33 }, { "type": "text", "text": "from TestModel.models import Test,Contact,Tag ", "bbox": [ 146, 822, 398, 832 ], "page_idx": 33 }, { "type": "text", "text": "# Register your models here. ", "bbox": [ 146, 859, 300, 869 ], "page_idx": 33 }, { "type": "text", "text": "class TagInline(admin.TabularInline): ", "bbox": [ 146, 877, 339, 888 ], "page_idx": 33 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "model $=$ Tag \nclass ContactAdmin(admin.ModelAdmin): list_display $\\equiv$ ('name','age'，'email')#list inlines $=$ [TagInline] # Inline fieldsets $=$ ( ['Main',{ 'fields':('name','email'), }], ['Advance',{ 'classes':('collapse'), 'fields':('age'), }]} \n） \nadmin.site.register(Contact,ContactAdmin) \nadmin.site.register([Test]) ", "bbox": [ 147, 93, 374, 423 ], "page_idx": 34 }, { "type": "text", "text": "搜索功能", "text_level": 1, "bbox": [ 147, 451, 247, 470 ], "page_idx": 34 }, { "type": "text", "text": "search_fields 为该列表页增加搜索栏：", "bbox": [ 147, 513, 347, 525 ], "page_idx": 34 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "HelloWorld/TestModel/admin.py:文件代码： \nfrom django.contrib import admin \nfrom TestModel.models import Test,Contact,Tag", "guess_lang": "python", "bbox": [ 147, 550, 400, 600 ], "page_idx": 34 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "# Register your models here. \nclass TagInline(admin.TabularInline): model $=$ Tag \nclass ContactAdmin(admin.ModelAdmin): list_display $\\equiv$ ('name','age'，'email') #list search_fields $=$ ('name') inlines $=$ [TagInline] # Inline fieldsets $=$ ( ['Main',{ 'fields':('name','email'), }], ['Advance',{ 'classes':('collapse'), 'fields':('age'), ", "bbox": [ 147, 623, 371, 895 ], "page_idx": 34 }, { "type": "text", "text": "}] ", "bbox": [ 174, 96, 184, 105 ], "page_idx": 35 }, { "type": "text", "text": ") ", "bbox": [ 161, 131, 168, 142 ], "page_idx": 35 }, { "type": "text", "text": "admin.site.register(Contact, ContactAdmin) ", "bbox": [ 147, 168, 376, 180 ], "page_idx": 35 }, { "type": "text", "text": "admin.site.register([Test]) ", "bbox": [ 147, 187, 282, 198 ], "page_idx": 35 }, { "type": "text", "text": "在 django2.0 后，定义外键和一对一关系的时候需要加 on_delete 选项，此参数为了避免两个表里的数据不一致问题，不然会报错：", "bbox": [ 146, 206, 840, 218 ], "page_idx": 35 }, { "type": "text", "text": "TypeError: __init__() missing 1 required positional argument: 'on_delete'。 ", "bbox": [ 147, 225, 561, 236 ], "page_idx": 35 }, { "type": "text", "text": "owner=models.ForeignKey(UserProfile,on_delete=models.CASCADE) --在老版本这个参数（models.CASCADE）是默认值参数", "bbox": [ 146, 243, 815, 254 ], "page_idx": 35 }, { "type": "text", "text": "说明：on_delete 有 CASCADE、PROTECT、SET_NULL、SET_DEFAULT、SET() 五个可选择的值。", "bbox": [ 146, 262, 677, 273 ], "page_idx": 35 }, { "type": "list", "sub_type": "text", "list_items": [ "CASCADE：此值设置，是级联删除。", ". PROTECT：此值设置，是会报完整性错误。", ". SET_NULL：此值设置，会把外键设置为null，前提是允许为null。 ", ". SET_DEFAULT：此值设置，会把设置为外键的默认值。 ", "SET()：此值设置，会调用外面的值，可以是一个函数。一般情况下使用CASCADE 就可以了。" ], "bbox": [ 176, 280, 700, 366 ], "page_idx": 35 }, { "type": "text", "text": "如果你之前还未创建表结构，可使用以下命令创建：", "bbox": [ 147, 373, 416, 384 ], "page_idx": 35 }, { "type": "text", "text": "$ python manage.py makemigrations TestModel # 让 Django 知道我们在我们的模型有一些变更", "bbox": [ 146, 391, 648, 403 ], "page_idx": 35 }, { "type": "text", "text": "$ python manage.py migrate TestModel # 创建表结构", "bbox": [ 147, 410, 435, 422 ], "page_idx": 35 }, { "type": "text", "text": "数据库添加", "text_level": 1, "bbox": [ 147, 451, 267, 470 ], "page_idx": 35 }, { "type": "text", "text": "规则配置：", "bbox": [ 147, 513, 203, 524 ], "page_idx": 35 }, { "type": "text", "text": "app01/urls.py: 文件代码：", "bbox": [ 146, 550, 280, 561 ], "page_idx": 35 }, { "type": "text", "text": "from django.contrib import admin ", "bbox": [ 147, 568, 322, 579 ], "page_idx": 35 }, { "type": "text", "text": "from django.urls import path ", "bbox": [ 147, 587, 297, 598 ], "page_idx": 35 }, { "type": "text", "text": "from . import views ", "bbox": [ 147, 606, 250, 615 ], "page_idx": 35 }, { "type": "text", "text": "urlpatterns = [ ", "bbox": [ 147, 643, 223, 653 ], "page_idx": 35 }, { "type": "text", "text": "path('add_book/', views.add_book), ", "bbox": [ 161, 661, 347, 671 ], "page_idx": 35 }, { "type": "text", "text": "] ", "bbox": [ 147, 681, 156, 690 ], "page_idx": 35 }, { "type": "text", "text": "方式一：模型类实例化对象", "bbox": [ 147, 697, 292, 709 ], "page_idx": 35 }, { "type": "text", "text": "需从 app 目录引入 models.py 文件：", "bbox": [ 147, 734, 334, 747 ], "page_idx": 35 }, { "type": "text", "text": "from app 目录 import models ", "bbox": [ 146, 772, 300, 783 ], "page_idx": 35 }, { "type": "text", "text": "并且实例化对象后要执行 对象.save() 才能在数据库中新增成功。", "bbox": [ 146, 791, 480, 802 ], "page_idx": 35 }, { "type": "text", "text": "app01/views.py: 文件代码：", "bbox": [ 146, 828, 290, 839 ], "page_idx": 35 }, { "type": "text", "text": "from django.shortcuts import render,HttpResponse ", "bbox": [ 146, 846, 413, 857 ], "page_idx": 35 }, { "type": "text", "text": "from app01 import models ", "bbox": [ 147, 865, 287, 876 ], "page_idx": 35 }, { "type": "text", "text": "def add_book(request): ", "bbox": [ 147, 883, 272, 895 ], "page_idx": 35 }, { "type": "text", "text": "book $=$ models.Book(title $! = \"$ 菜鸟教程\",price=300,publish=\"菜鸟出版社\",pub_date=\"2008-8-8\") ", "bbox": [ 156, 93, 640, 105 ], "page_idx": 36 }, { "type": "text", "text": "book.save() ", "bbox": [ 159, 114, 225, 124 ], "page_idx": 36 }, { "type": "text", "text": "return HttpResponse( $\" < p >$ 数据添加成功！ $< / { \\mathsf { p } } > \"$ )", "bbox": [ 159, 131, 415, 143 ], "page_idx": 36 }, { "type": "text", "text": "方式二：通过 ORM 提供的 objects 提供的方法create 来实现（推荐）", "bbox": [ 147, 149, 505, 161 ], "page_idx": 36 }, { "type": "text", "text": "app01/views.py: 文件代码：", "bbox": [ 147, 187, 290, 199 ], "page_idx": 36 }, { "type": "text", "text": "from django.shortcuts import render,HttpResponse ", "bbox": [ 147, 206, 413, 217 ], "page_idx": 36 }, { "type": "text", "text": "from app01 import models ", "bbox": [ 147, 225, 287, 235 ], "page_idx": 36 }, { "type": "text", "text": "def add_book(request): ", "bbox": [ 147, 243, 272, 254 ], "page_idx": 36 }, { "type": "text", "text": "books $=$ models.Book.objects.create(title=\"如来神掌\",price=200,publish=\"功夫出版社\",pub_date=\"2010-10-10\") ", "bbox": [ 159, 262, 739, 273 ], "page_idx": 36 }, { "type": "text", "text": "print(books, type(books)) # Book object (18) ", "bbox": [ 159, 280, 393, 291 ], "page_idx": 36 }, { "type": "text", "text": "return HttpResponse(\"

数据添加成功！

\")", "bbox": [ 159, 299, 413, 310 ], "page_idx": 36 }, { "type": "text", "text": "查找", "text_level": 1, "bbox": [ 147, 338, 200, 357 ], "page_idx": 36 }, { "type": "text", "text": "使用 all() 方法来查询所有内容。", "bbox": [ 144, 400, 388, 414 ], "page_idx": 36 }, { "type": "text", "text": "返回的是 QuerySet 类型数据，类似于 list，里面放的是一个个模型类的对象，可用索引下标取出模型类的对象。", "bbox": [ 144, 418, 847, 451 ], "page_idx": 36 }, { "type": "text", "text": "（for I in books）", "bbox": [ 159, 456, 268, 470 ], "page_idx": 36 }, { "type": "text", "text": "books $=$ models.Book.objects.all() ", "bbox": [ 159, 476, 339, 487 ], "page_idx": 36 }, { "type": "text", "text": "print(books,type(books)) # QuerySet 类型，类似于 list，访问 url 时数据显示在命令行窗口中。", "bbox": [ 159, 494, 642, 505 ], "page_idx": 36 }, { "type": "text", "text": "查询符合条件的数据。", "text_level": 1, "bbox": [ 146, 535, 371, 555 ], "page_idx": 36 }, { "type": "text", "text": "filter() 方法", "bbox": [ 146, 598, 208, 608 ], "page_idx": 36 }, { "type": "text", "text": "返回的是 QuerySet 类型数据，类似于 list，里面放的是满足条件的模型类的对象，可用索引下标取出模型类的对象。", "bbox": [ 144, 615, 746, 627 ], "page_idx": 36 }, { "type": "text", "text": "pk=3 的意思是主键 primary key=3，相当于 id=3。", "bbox": [ 146, 653, 403, 664 ], "page_idx": 36 }, { "type": "text", "text": "因为 id 在 pycharm 里有特殊含义，是看内存地址的内置函数 id()，因此用 pk。", "bbox": [ 144, 690, 549, 702 ], "page_idx": 36 }, { "type": "text", "text": "books $=$ models.Book.objects.filter(pk=5) ", "bbox": [ 157, 726, 376, 738 ], "page_idx": 36 }, { "type": "text", "text": "print(books) ", "bbox": [ 159, 746, 226, 756 ], "page_idx": 36 }, { "type": "text", "text": "print(\"//////////////////////////////////////\") ", "bbox": [ 159, 764, 327, 775 ], "page_idx": 36 }, { "type": "text", "text": "books $=$ models.Book.objects.filter(publish='菜鸟出版社', price=300) ", "bbox": [ 159, 783, 515, 794 ], "page_idx": 36 }, { "type": "text", "text": "print(books, type(books)) # QuerySet 类型，类似于 list。", "bbox": [ 159, 802, 453, 813 ], "page_idx": 36 }, { "type": "text", "text": "查询不符合条件的数据。", "text_level": 1, "bbox": [ 147, 101, 394, 120 ], "page_idx": 37 }, { "type": "text", "text": "exclude() 方法", "bbox": [ 144, 162, 226, 174 ], "page_idx": 37 }, { "type": "text", "text": "返回的是 QuerySet 类型数据，类似于 list，里面放的是不满足条件的模型类的对象，可用索引下标取出模型类的对象。", "bbox": [ 144, 181, 757, 193 ], "page_idx": 37 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "books $=$ models.Book.objectsexclude(pk=5) ", "bbox": [ 159, 199, 394, 211 ], "page_idx": 37 }, { "type": "text", "text": "print(books) ", "bbox": [ 159, 218, 226, 229 ], "page_idx": 37 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "print(\"|||||||||||||||||||||||||||||||||\") ", "guess_lang": "txt", "bbox": [ 159, 237, 327, 248 ], "page_idx": 37 }, { "type": "text", "text": "books $=$ models.Book.objects.exclude(publish='菜鸟出版社', price=300) ", "bbox": [ 159, 255, 534, 267 ], "page_idx": 37 }, { "type": "text", "text": "print(books, type(books)) # QuerySet 类型，类似于 list。", "bbox": [ 159, 274, 455, 286 ], "page_idx": 37 }, { "type": "text", "text": "get() 方法", "text_level": 1, "bbox": [ 146, 315, 260, 336 ], "page_idx": 37 }, { "type": "text", "text": "用于查询符合条件的返回模型类的对象符合条件的对象只能为一个，如果符合筛选条件的对象超过了一个或者没有一个都会抛出错误。", "bbox": [ 144, 376, 840, 388 ], "page_idx": 37 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "books $=$ models.Book.objects.get(pk=5) ", "bbox": [ 159, 395, 371, 407 ], "page_idx": 37 }, { "type": "text", "text": "books $=$ models.Book.objects.get ${ \\tt p k } { = } 1 8$ ) # 报错，没有符合条件的对象", "bbox": [ 159, 414, 534, 425 ], "page_idx": 37 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "books = models.Book.objects.get(price=200) # 报错，符合条件的对象超过一个 ", "guess_lang": "txt", "bbox": [ 159, 432, 576, 444 ], "page_idx": 37 }, { "type": "text", "text": "print(books, type(books)) # 模型类的对象 ", "bbox": [ 159, 451, 381, 463 ], "page_idx": 37 }, { "type": "text", "text": "排序 ", "text_level": 1, "bbox": [ 146, 492, 198, 511 ], "page_idx": 37 }, { "type": "text", "text": "order_by() ", "bbox": [ 144, 554, 205, 565 ], "page_idx": 37 }, { "type": "text", "text": "返回的是 QuerySet类型数据，类似于list，里面放的是排序后的模型类的对象，可用索引下标取出模型类的对象。", "bbox": [ 144, 571, 732, 583 ], "page_idx": 37 }, { "type": "text", "text": "注意：", "bbox": [ 146, 609, 179, 620 ], "page_idx": 37 }, { "type": "list", "sub_type": "text", "list_items": [ "a、参数的字段名要加引号。", "b、降序为在字段前面加个负号-。" ], "bbox": [ 146, 646, 322, 676 ], "page_idx": 37 }, { "type": "text", "text": "books $=$ models.Book.objects.order_by(\"price\") # 查询所有，按照价格升序排列", "bbox": [ 159, 684, 576, 695 ], "page_idx": 37 }, { "type": "text", "text": "books $=$ models.Book.objects.order_by(\"-price\") # 查询所有，按照价格降序排列", "bbox": [ 159, 702, 579, 714 ], "page_idx": 37 }, { "type": "text", "text": "对查询结果进行反转。", "text_level": 1, "bbox": [ 146, 744, 369, 762 ], "page_idx": 37 }, { "type": "text", "text": "reverse() 方法", "bbox": [ 144, 804, 226, 816 ], "page_idx": 37 }, { "type": "text", "text": "返回的是 QuerySe t类型数据，类似于 list，里面放的是反转后的模型类的对象，可用索引下标取出模型类的对象。", "bbox": [ 144, 822, 736, 835 ], "page_idx": 37 }, { "type": "text", "text": "# 按照价格升序排列：降序再反转 ", "bbox": [ 159, 860, 339, 872 ], "page_idx": 37 }, { "type": "text", "text": "books $=$ models.Book.objects.order_by(\"-price\").reverse()", "bbox": [ 159, 879, 463, 890 ], "page_idx": 37 }, { "type": "text", "text": "查询数据的数量", "text_level": 1, "bbox": [ 147, 101, 317, 120 ], "page_idx": 38 }, { "type": "text", "text": "返回的数据是整数。", "text_level": 1, "bbox": [ 146, 161, 302, 177 ], "page_idx": 38 }, { "type": "text", "text": "count() 方法", "bbox": [ 147, 181, 215, 193 ], "page_idx": 38 }, { "type": "text", "text": "books $=$ models.Book.objects.count() # 查询所有数据的数量", "bbox": [ 159, 199, 478, 212 ], "page_idx": 38 }, { "type": "text", "text": "books $=$ models.Book.objects.filter(price=200).count() # 查询符合条件数据的数量", "bbox": [ 159, 218, 586, 231 ], "page_idx": 38 }, { "type": "text", "text": "first() 方法返回第一条数据返回的数据是模型类的对象也可以用索引下标 [0]。", "bbox": [ 146, 237, 544, 249 ], "page_idx": 38 }, { "type": "text", "text": "books $=$ models.Book.objects.first() # 返回所有数据的第一条数据", "bbox": [ 159, 255, 502, 267 ], "page_idx": 38 }, { "type": "text", "text": "last() 方法返回最后一条数据返回的数据是模型类的对象不能用索引下标[-1]，ORM 没有逆序索引。", "bbox": [ 146, 274, 660, 286 ], "page_idx": 38 }, { "type": "text", "text": "books $=$ models.Book.objects.last() # 返回所有数据的最后一条数据", "bbox": [ 159, 292, 514, 304 ], "page_idx": 38 }, { "type": "text", "text": "是否存在数据", "text_level": 1, "bbox": [ 147, 334, 294, 353 ], "page_idx": 38 }, { "type": "text", "text": "exists() 方法用于判断查询的结果 QuerySet 列表里是否有数据。", "bbox": [ 146, 395, 477, 407 ], "page_idx": 38 }, { "type": "text", "text": "返回的数据类型是布尔，有为 true，没有为 false。", "bbox": [ 146, 432, 406, 444 ], "page_idx": 38 }, { "type": "text", "text": "注意：判断的数据类型只能为 QuerySet 类型数据，不能为整型和模型类的对象。", "bbox": [ 146, 469, 564, 481 ], "page_idx": 38 }, { "type": "text", "text": "books $=$ models.Book.objects.exists()", "bbox": [ 159, 506, 359, 518 ], "page_idx": 38 }, { "type": "text", "text": "# 报错，判断的数据类型只能为QuerySet类型数据，不能为整型", "bbox": [ 159, 525, 500, 537 ], "page_idx": 38 }, { "type": "text", "text": "books $=$ models.Book.objects.count().exists()", "bbox": [ 159, 543, 400, 555 ], "page_idx": 38 }, { "type": "text", "text": "# 报错，判断的数据类型只能为QuerySet类型数据，不能为模型类对象", "bbox": [ 159, 562, 534, 574 ], "page_idx": 38 }, { "type": "text", "text": "books $=$ models.Book.objects.first().exists()", "bbox": [ 159, 581, 389, 592 ], "page_idx": 38 }, { "type": "text", "text": "查询数据", "text_level": 1, "bbox": [ 147, 621, 247, 640 ], "page_idx": 38 }, { "type": "text", "text": "values() 方法用于查询部分字段的数据。", "bbox": [ 146, 684, 354, 695 ], "page_idx": 38 }, { "type": "text", "text": "返回的是 QuerySet 类型数据，类似于 list，里面不是模型类的对象，而是一个可迭代的字典序列，字典里的键是字段，值是数据。", "bbox": [ 144, 720, 816, 732 ], "page_idx": 38 }, { "type": "text", "text": "注意：", "bbox": [ 147, 758, 179, 769 ], "page_idx": 38 }, { "type": "text", "text": "参数的字段名要加引号", "bbox": [ 147, 795, 268, 806 ], "page_idx": 38 }, { "type": "text", "text": "想要字段名和数据用 values", "bbox": [ 147, 814, 294, 825 ], "page_idx": 38 }, { "type": "text", "text": "books $=$ models.Book.objects.values(\"pk\",\"price\") ", "bbox": [ 159, 832, 420, 843 ], "page_idx": 38 }, { "type": "text", "text": "print(books[0][\"price\"],type(books)) # 得到的是第一条记录的 price 字段的数据", "bbox": [ 159, 851, 564, 862 ], "page_idx": 38 }, { "type": "text", "text": "查询数据 2", "text_level": 1, "bbox": [ 147, 101, 265, 120 ], "page_idx": 39 }, { "type": "text", "text": "values_list() 方法用于查询部分字段的数据。", "bbox": [ 144, 162, 381, 174 ], "page_idx": 39 }, { "type": "text", "text": "返回的是 QuerySet 类型数据，类似于 list，里面不是模型类的对象，而是一个个元组，元组里放的是查询字段对应的数据。", "bbox": [ 144, 181, 781, 193 ], "page_idx": 39 }, { "type": "text", "text": "注意：", "bbox": [ 146, 199, 181, 211 ], "page_idx": 39 }, { "type": "list", "sub_type": "text", "list_items": [ "参数的字段名要加引号", ". 只想要数据用 values_list" ], "bbox": [ 176, 218, 339, 247 ], "page_idx": 39 }, { "type": "text", "text": "books $=$ models.Book.objects.values_list(\"price\",\"publish\") ", "bbox": [ 159, 255, 465, 266 ], "page_idx": 39 }, { "type": "text", "text": "print(books) ", "bbox": [ 159, 274, 228, 285 ], "page_idx": 39 }, { "type": "text", "text": "print(books[0][0],type(books)) # 得到的是第一条记录的 price 字段的数据", "bbox": [ 159, 292, 539, 304 ], "page_idx": 39 }, { "type": "text", "text": "去重", "text_level": 1, "bbox": [ 147, 334, 200, 351 ], "page_idx": 39 }, { "type": "text", "text": "distinct() 方法用于对数据进行去重。", "bbox": [ 144, 395, 339, 407 ], "page_idx": 39 }, { "type": "text", "text": "返回的是 QuerySet 类型数据。", "bbox": [ 146, 414, 307, 425 ], "page_idx": 39 }, { "type": "text", "text": "注意：", "bbox": [ 146, 432, 181, 444 ], "page_idx": 39 }, { "type": "list", "sub_type": "text", "list_items": [ ". 对模型类的对象去重没有意义，因为每个对象都是一个不一样的存在。", "distinct() 一般是联合 values 或者 values_list 使用。" ], "bbox": [ 176, 451, 569, 481 ], "page_idx": 39 }, { "type": "text", "text": "def add_book(request): ", "bbox": [ 146, 506, 273, 518 ], "page_idx": 39 }, { "type": "text", "text": "# 查询一共有多少个出版社", "bbox": [ 159, 525, 304, 536 ], "page_idx": 39 }, { "type": "text", "text": "books $=$ models.Book.objects.values_list(\"publish\").distinct() # 对模型类的对象去重没有意义，因为每个对象都是一个不一样的存在。", "bbox": [ 157, 543, 847, 555 ], "page_idx": 39 }, { "type": "text", "text": "books $=$ models.Book.objects.distinct() ", "bbox": [ 159, 562, 366, 573 ], "page_idx": 39 }, { "type": "text", "text": "基于双下划线的模糊查询", "text_level": 1, "bbox": [ 146, 602, 411, 623 ], "page_idx": 39 }, { "type": "text", "text": "filter() 方法（exclude 同理）。", "bbox": [ 144, 665, 307, 676 ], "page_idx": 39 }, { "type": "text", "text": "注意：filter 中运算符号只能使用等于号 $=$ ，不能使用大于号 $>$ ，小于号 $<$ ，等等其他符号。", "bbox": [ 144, 683, 618, 695 ], "page_idx": 39 }, { "type": "text", "text": "_in 用于读取区间， $=$ 号后面为列表 。", "bbox": [ 146, 702, 347, 713 ], "page_idx": 39 }, { "type": "text", "text": "_gt 大于号 ， $=$ 号后面为数字。__gte 大于等于， $=$ 号后面为数字。__lt,__lte", "bbox": [ 146, 720, 554, 733 ], "page_idx": 39 }, { "type": "text", "text": "_range 在 ... 之间，左闭右闭区间， $=$ 号后面为两个元素的列表。", "bbox": [ 146, 739, 489, 751 ], "page_idx": 39 }, { "type": "text", "text": "_contains 包含， $=$ 号后面为字符串。", "bbox": [ 146, 758, 347, 769 ], "page_idx": 39 }, { "type": "text", "text": "_icontains 不区分大小写的包含， $=$ 号后面为字符串。", "bbox": [ 146, 776, 433, 788 ], "page_idx": 39 }, { "type": "text", "text": "_startswith 以指定字符开头， $=$ 号后面为字符串。", "bbox": [ 146, 795, 413, 806 ], "page_idx": 39 }, { "type": "text", "text": "_endswith 以指定字符结尾， $=$ 号后面为字符串。", "bbox": [ 146, 813, 410, 825 ], "page_idx": 39 }, { "type": "text", "text": "_year 是 DateField 数据类型的年份， $=$ 号后面为数字。__day/__month ", "bbox": [ 146, 832, 527, 844 ], "page_idx": 39 }, { "type": "text", "text": "删除 ", "text_level": 1, "bbox": [ 147, 101, 200, 120 ], "page_idx": 40 }, { "type": "text", "text": "方式一：使用模型类的 对象.delete()。", "bbox": [ 144, 162, 344, 174 ], "page_idx": 40 }, { "type": "text", "text": "返回值：元组，第一个元素为受影响的行数。", "bbox": [ 146, 181, 379, 192 ], "page_idx": 40 }, { "type": "text", "text": "books=models.Book.objects.filter(pk=8).first().delete() ", "bbox": [ 146, 199, 428, 211 ], "page_idx": 40 }, { "type": "text", "text": "方式二：使用 QuerySet 类型数据.delete()(推荐)", "bbox": [ 146, 218, 401, 230 ], "page_idx": 40 }, { "type": "text", "text": "返回值：元组，第一个元素为受影响的行数。", "bbox": [ 146, 237, 379, 248 ], "page_idx": 40 }, { "type": "text", "text": "books=models.Book.objects.filter(pk__in=[1,2]).delete() ", "bbox": [ 146, 255, 438, 267 ], "page_idx": 40 }, { "type": "list", "sub_type": "text", "list_items": [ "a. Django 删除数据时，会模仿 SQL约束 ON DELETE CASCADE 的行为，也就是删除一个对象时也会删除与它相关联的外键对象。", ". b. delete() 方法是 QuerySet 数据类型的方法，但并不适用于 Manager 本身。也就是想要删除所有数据，不能不写 all。" ], "bbox": [ 174, 274, 845, 323 ], "page_idx": 40 }, { "type": "text", "text": "books=models.Book.objects.delete() # 报错 ", "bbox": [ 146, 330, 388, 341 ], "page_idx": 40 }, { "type": "text", "text": "books=models.Book.objects.all().delete() # 删除成功 ", "bbox": [ 146, 348, 447, 360 ], "page_idx": 40 }, { "type": "text", "text": "修改", "text_level": 1, "bbox": [ 146, 388, 200, 407 ], "page_idx": 40 }, { "type": "text", "text": "方式一：", "bbox": [ 146, 451, 191, 462 ], "page_idx": 40 }, { "type": "text", "text": "模型类的对象.属性 $=$ 更改的属性值", "text_level": 1, "bbox": [ 146, 491, 514, 512 ], "page_idx": 40 }, { "type": "text", "text": "模型类的对象.save()", "bbox": [ 146, 554, 258, 565 ], "page_idx": 40 }, { "type": "text", "text": "返回值：编辑的模型类的对象。", "bbox": [ 146, 573, 309, 583 ], "page_idx": 40 }, { "type": "equation", "text": "$$\n\\text {b o o k s} = \\text {m o d e l s . B o o k . o b j e c t s . f i l t e r} (\\mathrm {p k} = 7). \\text {f i r s t ()}\n$$", "text_format": "latex", "bbox": [ 146, 590, 393, 602 ], "page_idx": 40 }, { "type": "equation", "text": "$$\n\\text {b o o k s . p r i c e} = 4 0 0\n$$", "text_format": "latex", "bbox": [ 146, 609, 243, 620 ], "page_idx": 40 }, { "type": "equation", "text": "$$\n\\mathsf {b o o k s . s a v e ()}\n$$", "text_format": "latex", "bbox": [ 146, 627, 218, 639 ], "page_idx": 40 }, { "type": "text", "text": "方式二：QuerySet 类型数据.update(字段名 $\\mathbf { \\tau } = \\mathbf { \\dot { \\tau } }$ 更改的数据)（推荐）", "bbox": [ 146, 646, 485, 658 ], "page_idx": 40 }, { "type": "text", "text": "返回值：整数，受影响的行数", "bbox": [ 146, 665, 304, 676 ], "page_idx": 40 }, { "type": "text", "text": "实例", "bbox": [ 147, 684, 174, 695 ], "page_idx": 40 }, { "type": "text", "text": "from django.shortcuts import render,HttpResponse ", "bbox": [ 146, 702, 420, 713 ], "page_idx": 40 }, { "type": "text", "text": "from app01 import models ", "bbox": [ 146, 720, 294, 731 ], "page_idx": 40 }, { "type": "text", "text": "def add_book(request): ", "bbox": [ 146, 739, 273, 750 ], "page_idx": 40 }, { "type": "text", "text": "books $=$ models.Book.objects.filter(pk__in=[7,8]).update(price=888) ", "bbox": [ 159, 758, 514, 769 ], "page_idx": 40 }, { "type": "text", "text": "ORM - 添加数据", "bbox": [ 146, 795, 236, 806 ], "page_idx": 40 }, { "type": "text", "text": "一对多(外键 ForeignKey)", "bbox": [ 146, 813, 285, 825 ], "page_idx": 40 }, { "type": "text", "text": "方式一: 传对象的形式，返回值的数据类型是对象，书籍对象。", "bbox": [ 146, 832, 468, 843 ], "page_idx": 40 }, { "type": "text", "text": "步骤：", "bbox": [ 146, 851, 179, 860 ], "page_idx": 40 }, { "type": "list", "sub_type": "text", "list_items": [ "a. 获取出版社对象", "b. 给书籍的出版社属性pulish 传出版社对象" ], "bbox": [ 174, 869, 436, 898 ], "page_idx": 40 }, { "type": "text", "text": "app01/views.py 文件代码：", "bbox": [ 146, 95, 292, 105 ], "page_idx": 41 }, { "type": "text", "text": "def add_book(request): ", "bbox": [ 146, 112, 273, 124 ], "page_idx": 41 }, { "type": "text", "text": "# 获取出版社对象", "bbox": [ 159, 131, 260, 143 ], "page_idx": 41 }, { "type": "text", "text": "pub_ob $=$ models.Publish.objects.filter(pk=1).first() ", "bbox": [ 159, 151, 428, 162 ], "page_idx": 41 }, { "type": "text", "text": "# 给书籍的出版社属性publish传出版社对象", "bbox": [ 159, 168, 396, 181 ], "page_idx": 41 }, { "type": "text", "text": "book $=$ models.Book.objects.create(title=\"菜鸟教程\", price $\\scriptstyle \\sum 0 0$ , pub_date $\\cdot = \"$ 2010-10-10\", publish=pub_obj) ", "bbox": [ 159, 187, 717, 200 ], "page_idx": 41 }, { "type": "text", "text": "print(book, type(book)) ", "bbox": [ 159, 206, 285, 218 ], "page_idx": 41 }, { "type": "text", "text": "return HttpResponse(book)", "bbox": [ 159, 225, 309, 236 ], "page_idx": 41 }, { "type": "text", "text": "方式二: 传对象 id 的形式(由于传过来的数据一般是 id,所以传对象 id 是常用的)。", "bbox": [ 146, 243, 556, 255 ], "page_idx": 41 }, { "type": "text", "text": "一对多中，设置外键属性的类(多的表)中，MySQL 中显示的字段名是:外键属性名_id。", "bbox": [ 146, 262, 589, 273 ], "page_idx": 41 }, { "type": "text", "text": "返回值的数据类型是对象，书籍对象。", "bbox": [ 146, 280, 344, 291 ], "page_idx": 41 }, { "type": "text", "text": "步骤：", "text_level": 1, "bbox": [ 146, 299, 179, 310 ], "page_idx": 41 }, { "type": "list", "sub_type": "text", "list_items": [ ". a. 获取出版社对象的 id", "b. 给书籍的关联出版社字段pulish_id 传出版社对象的 id" ], "bbox": [ 176, 317, 500, 347 ], "page_idx": 41 }, { "type": "text", "text": "多对多(ManyToManyField)：在第三张关系表中新增数据", "text_level": 1, "bbox": [ 146, 354, 448, 366 ], "page_idx": 41 }, { "type": "text", "text": "方式一: 传对象形式，无返回值。", "bbox": [ 146, 373, 315, 384 ], "page_idx": 41 }, { "type": "text", "text": "步骤：", "text_level": 1, "bbox": [ 146, 392, 179, 401 ], "page_idx": 41 }, { "type": "list", "sub_type": "text", "list_items": [ "a. 获取作者对象 ", ". b. 获取书籍对象", "c. 给书籍对象的 authors 属性用 add 方法传作者对象" ], "bbox": [ 176, 410, 482, 458 ], "page_idx": 41 }, { "type": "text", "text": "方式二: 传对象id形式，无返回值。", "bbox": [ 146, 464, 329, 476 ], "page_idx": 41 }, { "type": "text", "text": "步骤：", "text_level": 1, "bbox": [ 146, 483, 179, 495 ], "page_idx": 41 }, { "type": "list", "sub_type": "text", "list_items": [ "a. 获取作者对象的 id", ". b. 获取书籍对象", "c. 给书籍对象的 authors 属性用 add 方法传作者对象的 id" ], "bbox": [ 176, 502, 505, 551 ], "page_idx": 41 }, { "type": "text", "text": "app01/views.py 文件代码：", "bbox": [ 146, 558, 292, 570 ], "page_idx": 41 }, { "type": "text", "text": "def add_book(request): ", "bbox": [ 146, 577, 273, 588 ], "page_idx": 41 }, { "type": "text", "text": "# 获取作者对象", "bbox": [ 159, 595, 248, 606 ], "page_idx": 41 }, { "type": "text", "text": "chong $=$ models.Author.objects.filter(name=\"令狐冲\").first() ", "bbox": [ 159, 614, 468, 626 ], "page_idx": 41 }, { "type": "text", "text": "# 获取作者对象的id ", "bbox": [ 159, 632, 270, 643 ], "page_idx": 41 }, { "type": "text", "text": "pk $=$ chong.pk ", "bbox": [ 159, 651, 238, 661 ], "page_idx": 41 }, { "type": "text", "text": "# 获取书籍对象", "bbox": [ 159, 670, 248, 680 ], "page_idx": 41 }, { "type": "text", "text": "book $=$ models.Book.objects.filter(titl $\\mathrel { \\mathop : } \\mathbf { \\overline { { \\mathbf { \\Lambda } } } }$ \"冲灵剑法\").first() ", "bbox": [ 159, 688, 455, 699 ], "page_idx": 41 }, { "type": "text", "text": "# 给书籍对象的 authors 属性用 add 方法传作者对象的 id", "bbox": [ 159, 706, 458, 717 ], "page_idx": 41 }, { "type": "text", "text": "book.authors.add(pk) ", "bbox": [ 159, 725, 275, 736 ], "page_idx": 41 }, { "type": "text", "text": "关联管理器(对象调用)", "text_level": 1, "bbox": [ 146, 744, 265, 755 ], "page_idx": 41 }, { "type": "text", "text": "前提：", "text_level": 1, "bbox": [ 146, 762, 179, 772 ], "page_idx": 41 }, { "type": "list", "sub_type": "text", "list_items": [ "多对多（双向均有关联管理器）", "一对多（只有多的那个类的对象有关联管理器，即反向才有）" ], "bbox": [ 176, 780, 522, 810 ], "page_idx": 41 }, { "type": "text", "text": "语法格式：", "text_level": 1, "bbox": [ 146, 816, 203, 829 ], "page_idx": 41 }, { "type": "text", "text": "正向：属性名", "bbox": [ 146, 835, 221, 847 ], "page_idx": 41 }, { "type": "text", "text": "反向：小写类名加_set", "bbox": [ 146, 854, 270, 866 ], "page_idx": 41 }, { "type": "text", "text": "注意：一对多只能反向", "bbox": [ 146, 873, 268, 884 ], "page_idx": 41 }, { "type": "text", "text": "常用方法：", "text_level": 1, "bbox": [ 146, 892, 203, 903 ], "page_idx": 41 }, { "type": "text", "text": "add()：用于多对多，把指定的模型对象添加到关联对象集（关系表）中。", "bbox": [ 144, 95, 527, 105 ], "page_idx": 42 }, { "type": "text", "text": "注意：add() 在一对多(即外键)中，只能传对象（ *QuerySet数据类型），不能传 id（*[id表]）。", "bbox": [ 144, 112, 640, 124 ], "page_idx": 42 }, { "type": "text", "text": "*[ ] 的使用:", "bbox": [ 146, 133, 208, 143 ], "page_idx": 42 }, { "type": "text", "text": "# 方式一：传对象", "bbox": [ 146, 151, 243, 161 ], "page_idx": 42 }, { "type": "equation", "text": "$$\n\\text {b o o k} \\_ \\text {o b j} = \\text {m o d e l s . B o o k . o b j e c t s . g e t (i d = 1 0)}\n$$", "text_format": "latex", "bbox": [ 146, 168, 376, 180 ], "page_idx": 42 }, { "type": "equation", "text": "$$\n\\text {a u t o r} = \\text {m o d e l s . A u t o r . o b j e c t s . f i l t e r (i d \\_ g t = 2)}\n$$", "text_format": "latex", "bbox": [ 146, 187, 413, 199 ], "page_idx": 42 }, { "type": "text", "text": "book_obj.authors.add(*author_list) # 将 id 大于 2 的作者对象添加到这本书的作者集合中", "bbox": [ 144, 206, 608, 218 ], "page_idx": 42 }, { "type": "text", "text": "# 方式二：传对象id", "bbox": [ 146, 225, 255, 235 ], "page_idx": 42 }, { "type": "text", "text": "book_obj.authors.add(*[1,3]) # 将 id=1 和 id=3 的作者对象添加到这本书的作者集合中", "bbox": [ 144, 243, 591, 255 ], "page_idx": 42 }, { "type": "text", "text": "return HttpResponse(\"ok\")", "bbox": [ 146, 262, 292, 273 ], "page_idx": 42 }, { "type": "text", "text": "反向：小写表名_set", "bbox": [ 146, 280, 258, 292 ], "page_idx": 42 }, { "type": "equation", "text": "$$\ny i n g = \\text {m o d e l s . A u t h o r . o b j e c t s . f i l t e r} (\\text {n a m e} = ^ {\\prime \\prime} \\text {任 盈 盈} ^ {\\prime \\prime}). \\text {f i r s t ()}\n$$", "text_format": "latex", "bbox": [ 146, 299, 445, 311 ], "page_idx": 42 }, { "type": "equation", "text": "$$\n\\text {b o o k} = \\text {m o d e l s . B o o k . o b j e c t s . f i l t e r (t i t l e = ＂ 冲 灵 剑 法 ＂) . f i r s t ()}\n$$", "text_format": "latex", "bbox": [ 146, 317, 442, 329 ], "page_idx": 42 }, { "type": "equation", "text": "$$\n\\text {y i n g . b o o k \\_ s e t . a d d (b o o k)}\n$$", "text_format": "latex", "bbox": [ 146, 336, 280, 347 ], "page_idx": 42 }, { "type": "text", "text": "1. 正向查询（Forward Query）", "text_level": 1, "bbox": [ 146, 373, 312, 385 ], "page_idx": 42 }, { "type": "text", "text": "定义", "text_level": 1, "bbox": [ 146, 392, 176, 401 ], "page_idx": 42 }, { "type": "list", "sub_type": "text", "list_items": [ "从“持有外键的模型”访问“被关联的模型”。", "使用属性名直接访问关联对象。" ], "bbox": [ 176, 409, 458, 439 ], "page_idx": 42 }, { "type": "text", "text": "2. 反向查询（Reverse Query）", "text_level": 1, "bbox": [ 146, 447, 312, 458 ], "page_idx": 42 }, { "type": "text", "text": "定义", "text_level": 1, "bbox": [ 146, 466, 174, 476 ], "page_idx": 42 }, { "type": "list", "sub_type": "text", "list_items": [ "从“被关联的模型”访问“持有外键的模型”。", "默认使用小写类名_set 作为关联管理器名称。" ], "bbox": [ 176, 483, 458, 514 ], "page_idx": 42 }, { "type": "text", "text": "remove()：从关联对象集中移除执行的模型对象。", "bbox": [ 146, 521, 405, 533 ], "page_idx": 42 }, { "type": "text", "text": "对于 ForeignKey 对象，这个方法仅在 null=True（可以为空）时存在，无返回值。", "bbox": [ 144, 539, 566, 551 ], "page_idx": 42 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 146, 558, 174, 569 ], "page_idx": 42 }, { "type": "equation", "text": "$$\n\\text {a u t o r} = \\text {m o d e l s . A u t h o r . o b j e c t s . g e t (i d = 1)}\n$$", "text_format": "latex", "bbox": [ 146, 577, 381, 588 ], "page_idx": 42 }, { "type": "equation", "text": "$$\n\\text {b o o k} \\_ \\text {o b j} = \\text {m o d e l s . B o o k . o b j e c t s . g e t (i d = 1 1)}\n$$", "text_format": "latex", "bbox": [ 146, 595, 376, 606 ], "page_idx": 42 }, { "type": "equation", "text": "$$\n\\text {a t h o r} \\quad \\text {o b j . b o o k} \\quad \\text {s e t . r e m o v e} (\\text {b o o k} \\quad \\text {o b j})\n$$", "text_format": "latex", "bbox": [ 146, 614, 356, 625 ], "page_idx": 42 }, { "type": "text", "text": "clear()：从关联对象集中移除一切对象，删除关联，不会删除对象。", "bbox": [ 146, 632, 497, 644 ], "page_idx": 42 }, { "type": "text", "text": "对于 ForeignKey 对象，这个方法仅在 null=True（可以为空）时存在。", "bbox": [ 146, 651, 509, 662 ], "page_idx": 42 }, { "type": "text", "text": "无返回值。", "bbox": [ 146, 670, 203, 680 ], "page_idx": 42 }, { "type": "text", "text": "# 清空独孤九剑关联的所有作者", "bbox": [ 146, 688, 317, 699 ], "page_idx": 42 }, { "type": "equation", "text": "$$\n\\text {b o o k} = \\text {m o d e l s . B o o k . o b j e c t s . f i l t e r (t i t l e} = \\text {＂ 菜 鸟 教 程 ＂) . f i r s t ()}\n$$", "text_format": "latex", "bbox": [ 146, 707, 442, 718 ], "page_idx": 42 }, { "type": "equation", "text": "$$\n\\text {b o o k . a u t h o r s . c l e a r ()}\n$$", "text_format": "latex", "bbox": [ 146, 725, 255, 736 ], "page_idx": 42 }, { "type": "text", "text": "ORM 查询", "text_level": 1, "bbox": [ 146, 744, 205, 753 ], "page_idx": 42 }, { "type": "text", "text": "基于对象的跨表查询。", "bbox": [ 146, 762, 262, 772 ], "page_idx": 42 }, { "type": "text", "text": "正向：属性名称", "bbox": [ 146, 781, 233, 791 ], "page_idx": 42 }, { "type": "text", "text": "反向：小写类名_set", "bbox": [ 146, 799, 255, 810 ], "page_idx": 42 }, { "type": "text", "text": "一对多", "text_level": 1, "bbox": [ 146, 818, 186, 829 ], "page_idx": 42 }, { "type": "text", "text": "查询主键为 1 的书籍的出版社所在的城市（正向）。", "bbox": [ 146, 835, 415, 847 ], "page_idx": 42 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 146, 854, 174, 866 ], "page_idx": 42 }, { "type": "equation", "text": "$$\n\\begin{array}{l} \\text {b o o k} = \\text {m o d e l s . B o o k . o b j e c t s . f i l t e r (p k = 1 0) . f i r s t ()} \\\\ \\mathrm {r e s} = \\text {b o o k . p u b l i s h . c i t y} \\\\ \\end{array}\n$$", "text_format": "latex", "bbox": [ 146, 873, 394, 903 ], "page_idx": 42 }, { "type": "text", "text": "查询明教出版社出版的书籍名（反向）。", "bbox": [ 146, 95, 354, 105 ], "page_idx": 43 }, { "type": "text", "text": "反向：对象.小写类名_set(pub.book_set) 可以跳转到关联的表(书籍表)。", "bbox": [ 146, 112, 524, 124 ], "page_idx": 43 }, { "type": "text", "text": "pub.book_set.all()：取出书籍表的所有书籍对象，在一个 QuerySet 里，遍历取出一个个书籍对象。", "bbox": [ 146, 131, 663, 143 ], "page_idx": 43 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 151, 174, 161 ], "page_idx": 43 }, { "type": "equation", "text": "$$\n\\begin{array}{l} \\mathrm {p u b} = \\text {m o d e l s . P u b l i s h . o b j e c t s . f i l t e r (n a m e = \" 明 教 出 版 社\")}. \\text {f i r s t ()} \\\\ \\operatorname {r e s} = \\operatorname {p u b}. \\operatorname {b o o k} _ {\\text {s e t}}. \\operatorname {a l l} () \\\\ f o r i \\text {i n} \\\\ \\mathbf {p r i n t} (i. t i l e) \\\\ \\end{array}\n$$", "text_format": "latex", "bbox": [ 146, 168, 470, 235 ], "page_idx": 43 }, { "type": "text", "text": "一对一", "text_level": 1, "bbox": [ 147, 244, 186, 254 ], "page_idx": 43 }, { "type": "text", "text": "查询令狐冲的电话（正向）", "bbox": [ 146, 261, 284, 272 ], "page_idx": 43 }, { "type": "text", "text": "正向：对象.属性 (author.au_detail) 可以跳转到关联的表(作者详情表)", "bbox": [ 146, 280, 505, 292 ], "page_idx": 43 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 299, 174, 309 ], "page_idx": 43 }, { "type": "equation", "text": "$$\n\\text {a u t h o r} = \\text {m o d e l s . A u t h o r . o b j e c t s . f i l t e r (n a m e = \" 令 狐 冲\") . f i r s t ()}\n$$", "text_format": "latex", "bbox": [ 146, 317, 455, 329 ], "page_idx": 43 }, { "type": "equation", "text": "$$\n\\mathrm {r e s} = \\text {a u t h o r}.\n$$", "text_format": "latex", "bbox": [ 147, 336, 280, 346 ], "page_idx": 43 }, { "type": "equation", "text": "$$\n\\operatorname {p r i n t} (\\text {r e s}, \\text {t y p e} (\\text {r e s}))\n$$", "text_format": "latex", "bbox": [ 147, 355, 253, 366 ], "page_idx": 43 }, { "type": "text", "text": "查询所有住址在黑木崖的作者的姓名（反向）。", "bbox": [ 146, 373, 389, 384 ], "page_idx": 43 }, { "type": "text", "text": "一对一的反向，用对象.小写类名即可，不用加_set。", "bbox": [ 146, 391, 423, 403 ], "page_idx": 43 }, { "type": "text", "text": "反向：对象.小写类名(addr.author)可以跳转到关联的表(作者表)。", "bbox": [ 146, 410, 480, 420 ], "page_idx": 43 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 429, 174, 439 ], "page_idx": 43 }, { "type": "equation", "text": "$$\n\\begin{array}{l} \\text {a d d r} = \\text {m o d e l s . A u t h o r D e a t i l . o b j e c t s . f i l t e r} (\\text {a d d r} = ^ {\\prime \\prime} \\text {黑 木 崖}) ^ {\\prime \\prime}). \\text {f i r s t} () \\\\ \\text {r e s} = \\text {a d d r . a u t h o r . n a m e} \\\\ \\operatorname {p r i n t} (\\text {r e s}, \\text {t y p e} (\\text {r e s})) \\\\ \\end{array}\n$$", "text_format": "latex", "bbox": [ 146, 447, 470, 495 ], "page_idx": 43 }, { "type": "text", "text": "多对多", "text_level": 1, "bbox": [ 147, 502, 186, 513 ], "page_idx": 43 }, { "type": "text", "text": "菜鸟教程所有作者的名字以及手机号（正向）。", "bbox": [ 146, 521, 389, 532 ], "page_idx": 43 }, { "type": "text", "text": "正向：对象.属性(book.authors)可以跳转到关联的表(作者表)。", "bbox": [ 146, 539, 472, 551 ], "page_idx": 43 }, { "type": "text", "text": "作者表里没有作者电话，因此再次通过对象.属性(i.au_detail)跳转到关联的表（作者详情表）。", "bbox": [ 146, 558, 635, 570 ], "page_idx": 43 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 577, 174, 588 ], "page_idx": 43 }, { "type": "equation", "text": "$$\n\\text {b o o k} = \\text {m o d e l s . B o o k . o b j e c t s . f i l t e r (t i t l e = \" 菜 鸟 教 程 ) . f i r s t ()}\n$$", "text_format": "latex", "bbox": [ 146, 595, 440, 607 ], "page_idx": 43 }, { "type": "equation", "text": "$$\n\\mathrm {r e s} = \\text {b o o k . a u t h o r s . a l l ()}\n$$", "text_format": "latex", "bbox": [ 147, 614, 270, 625 ], "page_idx": 43 }, { "type": "equation", "text": "$$\nf o r i n \\text {r e s}:\n$$", "text_format": "latex", "bbox": [ 147, 633, 208, 643 ], "page_idx": 43 }, { "type": "equation", "text": "$$\n\\text {p r i n t} (\\mathrm {i . n a m e}, \\mathrm {i . a u} _ {\\text {d e t a l}}. \\text {t e l})\n$$", "text_format": "latex", "bbox": [ 161, 651, 309, 662 ], "page_idx": 43 }, { "type": "text", "text": "查询任我行出过的所有书籍的名字（反向）。", "bbox": [ 146, 669, 379, 681 ], "page_idx": 43 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 688, 174, 697 ], "page_idx": 43 }, { "type": "equation", "text": "$$\n\\begin{array}{l} \\text {a u t h o r} = \\text {m o d e l s . A u t h o r . o b j e c t s . f i l t e r (n a m e} = ^ {\\prime \\prime} \\text {任 我 行}) ^ {\\prime \\prime}. \\text {f i r s t ()} \\\\ \\operatorname {r e s} = \\text {a u t h o r . b o o k \\_ s e t . a l l ()} \\\\ f o r i n \\text {r e s}: \\\\ \\mathbf {p r i n t} (i. t i l e) \\\\ \\end{array}\n$$", "text_format": "latex", "bbox": [ 146, 707, 455, 772 ], "page_idx": 43 }, { "type": "text", "text": "正向：属性名称__跨表的属性名称反向：小写类名__跨表的属性名称", "bbox": [ 146, 780, 509, 791 ], "page_idx": 43 }, { "type": "text", "text": "一对多", "text_level": 1, "bbox": [ 147, 799, 186, 809 ], "page_idx": 43 }, { "type": "text", "text": "查询菜鸟出版社出版过的所有书籍的名字与价格。", "bbox": [ 146, 816, 401, 829 ], "page_idx": 43 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 837, 174, 847 ], "page_idx": 43 }, { "type": "equation", "text": "$$\n\\text {r e s} = \\text {m o d e l s . B o o k . o b j e c t s . f i l t e r (p u b l i s h \\_ n a m e = \" 菜 鸟 出 版 社\") . v a l u e s \\_ l i s t (\"} t h i t e , \" p r i c e \")\n$$", "text_format": "latex", "bbox": [ 146, 854, 608, 866 ], "page_idx": 43 }, { "type": "text", "text": "正向：属性名称__跨表的属性名称反向：小写类名__跨表的属性名称", "bbox": [ 146, 873, 509, 884 ], "page_idx": 43 }, { "type": "text", "text": "一对多", "text_level": 1, "bbox": [ 147, 892, 186, 903 ], "page_idx": 43 }, { "type": "text", "text": "查询菜鸟出版社出版过的所有书籍的名字与价格。", "bbox": [ 146, 95, 403, 105 ], "page_idx": 44 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 146, 112, 174, 124 ], "page_idx": 44 }, { "type": "text", "text": "res $=$ models.Book.objects.filter(publish__name=\"菜鸟出版社\").values_list(\"title\", \"price\") ", "bbox": [ 144, 131, 608, 143 ], "page_idx": 44 }, { "type": "text", "text": "反向：通过 小写类名__跨表的属性名称（book__title，book__price）跨表获取数据。", "bbox": [ 146, 151, 600, 162 ], "page_idx": 44 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 146, 168, 174, 180 ], "page_idx": 44 }, { "type": "text", "text": "res $=$ models.Publish.objects.filter(name=\"菜鸟出版社\").values_list(\"book__title\",\"book__price\") ", "bbox": [ 144, 187, 643, 199 ], "page_idx": 44 }, { "type": "text", "text": "return HttpResponse(\"ok\")", "bbox": [ 146, 206, 290, 217 ], "page_idx": 44 }, { "type": "text", "text": "多对多", "text_level": 1, "bbox": [ 146, 224, 186, 235 ], "page_idx": 44 }, { "type": "text", "text": "查询任我行出过的所有书籍的名字。", "bbox": [ 146, 243, 332, 254 ], "page_idx": 44 }, { "type": "text", "text": "正向：通过 属性名称__跨表的属性名称(authors__name) 跨表获取数据：", "bbox": [ 146, 261, 524, 273 ], "page_idx": 44 }, { "type": "text", "text": "res $=$ models.Book.objects.filter(authors__name=\"任我行\").values_list(\"title\") ", "bbox": [ 146, 280, 547, 292 ], "page_idx": 44 }, { "type": "text", "text": "反向：通过 小写类名__跨表的属性名称（book__title） 跨表获取数据：", "bbox": [ 146, 299, 514, 311 ], "page_idx": 44 }, { "type": "text", "text": "res $=$ models.Author.objects.filter(name=\"任我行\").values_list(\"book__title\") ", "bbox": [ 146, 317, 541, 329 ], "page_idx": 44 }, { "type": "text", "text": "一对一", "text_level": 1, "bbox": [ 146, 336, 186, 346 ], "page_idx": 44 }, { "type": "text", "text": "查询任我行的手机号。", "bbox": [ 146, 354, 260, 365 ], "page_idx": 44 }, { "type": "text", "text": "正向：通过属性名称__跨表的属性名称(au_detail__tel) 跨表获取数据。", "bbox": [ 146, 372, 519, 384 ], "page_idx": 44 }, { "type": "text", "text": "res $=$ models.Author.objects.filter(name=\"任我行\").values_list(\"au_detail__tel\") ", "bbox": [ 146, 391, 557, 403 ], "page_idx": 44 }, { "type": "text", "text": "反向：通过小写类名__跨表的属性名称（author__name）跨表获取数据。", "bbox": [ 146, 410, 537, 420 ], "page_idx": 44 }, { "type": "text", "text": "res $=$ models.AuthorDetail.objects.filter(author__name=\"任我行\").values_list(\"tel\") ", "bbox": [ 146, 428, 573, 439 ], "page_idx": 44 }, { "type": "text", "text": "Django ORM – 多表实例（聚合与分组查询）", "text_level": 1, "bbox": [ 146, 447, 381, 458 ], "page_idx": 44 }, { "type": "text", "text": "聚合查询（aggregate）", "text_level": 1, "bbox": [ 146, 464, 270, 476 ], "page_idx": 44 }, { "type": "text", "text": "聚合查询函数是对一组值执行计算，并返回单个值。", "bbox": [ 146, 483, 413, 495 ], "page_idx": 44 }, { "type": "text", "text": "Django 使用聚合查询前要先从 django.db.models 引入 Avg、Max、Min、Count、Sum（首字母大写）。", "bbox": [ 146, 502, 685, 514 ], "page_idx": 44 }, { "type": "text", "text": "from django.db.models import Avg,Max,Min,Count,Sum # 引入函数", "bbox": [ 146, 521, 509, 532 ], "page_idx": 44 }, { "type": "text", "text": "聚合查询返回值的数据类型是字典。", "bbox": [ 146, 539, 332, 551 ], "page_idx": 44 }, { "type": "text", "text": "聚合函数 aggregate() 是 QuerySet 的一个终止子句， 生成的一个汇总值，相当于 count()。", "bbox": [ 146, 558, 613, 570 ], "page_idx": 44 }, { "type": "text", "text": "使用 aggregate() 后，数据类型就变为字典，不能再使用 QuerySet 数据类型的一些 API 了。", "bbox": [ 146, 576, 620, 588 ], "page_idx": 44 }, { "type": "text", "text": "日期数据类型(DateField)可以用 Max 和 Min。", "bbox": [ 146, 595, 381, 606 ], "page_idx": 44 }, { "type": "text", "text": "返回的字典中：键的名称默认是（属性名称加上__聚合函数名），值是计算出来的聚合值。", "bbox": [ 146, 613, 616, 625 ], "page_idx": 44 }, { "type": "text", "text": "如果要自定义返回字典的键的名称，可以起别名：", "bbox": [ 146, 632, 403, 643 ], "page_idx": 44 }, { "type": "text", "text": "aggregate(别名 $=$ 聚合函数名(\"属性名称\"))", "bbox": [ 146, 651, 369, 662 ], "page_idx": 44 }, { "type": "text", "text": "分组查询（annotate）", "text_level": 1, "bbox": [ 146, 688, 263, 699 ], "page_idx": 44 }, { "type": "text", "text": "分组查询一般会用到聚合函数，所以使用前要先从 django.db.models 引入 Avg,Max,Min,Count,Sum（首字母大写）。", "bbox": [ 144, 706, 751, 718 ], "page_idx": 44 }, { "type": "text", "text": "from django.db.models import Avg,Max,Min,Count,Sum # 引入函数", "bbox": [ 146, 725, 509, 736 ], "page_idx": 44 }, { "type": "text", "text": "返回值：", "text_level": 1, "bbox": [ 146, 743, 191, 753 ], "page_idx": 44 }, { "type": "list", "sub_type": "text", "list_items": [ "分组后，用 values 取值，则返回值是 QuerySet 数据类型里面为一个个字典；", "分组后，用 values_list 取值，则返回值是 QuerySet 数据类型里面为一个个元组。" ], "bbox": [ 174, 762, 626, 791 ], "page_idx": 44 }, { "type": "text", "text": "MySQL 中的 limit 相当于 ORM 中的 QuerySet 数据类型的切片。", "bbox": [ 146, 799, 478, 810 ], "page_idx": 44 }, { "type": "text", "text": "注意：", "text_level": 1, "bbox": [ 146, 816, 179, 829 ], "page_idx": 44 }, { "type": "text", "text": "annotate 里面放聚合函数。", "bbox": [ 146, 835, 287, 847 ], "page_idx": 44 }, { "type": "list", "sub_type": "text", "list_items": [ "values 或者 values_list 放在 annotate 前面：values 或者 values_list 是声明以什么字段分组，annotate 执行分组。前者相当于GROUP BY,后者相当于聚合函数", "values 或者 values_list 放在 annotate 后面： annotate 表示直接以当前表的 pk 执行分组，values 或者 values_list 表示查询哪" ], "bbox": [ 144, 854, 847, 903 ], "page_idx": 44 }, { "type": "text", "text": "些字段， 并且要将 annotate 里的聚合函数起别名，在 values 或者 values_list 里写其别名。", "bbox": [ 176, 95, 645, 107 ], "page_idx": 45 }, { "type": "text", "text": "annotate 里相当于聚合函数，value 相当于 groupby 了", "text_level": 1, "bbox": [ 147, 114, 468, 126 ], "page_idx": 45 }, { "type": "code", "sub_type": "algorithm", "code_caption": [], "code_body": "res $=$ models.Publish.objects.values(\"name\"). annotate(in_price $\\equiv$ Min(\"book_price\")) \nprint(res) \nres $=$ models.Book.objects annotate(c $=$ Count(\"authors_name\").values(\"title\",\"c\") \nprint(res) ", "bbox": [ 146, 131, 594, 200 ], "page_idx": 45 }, { "type": "text", "text": "F() 查询", "text_level": 1, "bbox": [ 147, 206, 193, 218 ], "page_idx": 45 }, { "type": "text", "text": "F() 的实例可以在查询中引用字段，来比较同一个 model 实例中两个不同字段的值。", "bbox": [ 146, 224, 576, 236 ], "page_idx": 45 }, { "type": "text", "text": "之前构造的过滤器都只是将字段值与某个常量做比较，如果想要对两个字段的值做比较，就需要用到 F()。", "bbox": [ 146, 243, 690, 255 ], "page_idx": 45 }, { "type": "text", "text": "使用前要先从 django.db.models 引入 F:", "bbox": [ 146, 262, 357, 273 ], "page_idx": 45 }, { "type": "text", "text": "from django.db.models import F ", "bbox": [ 146, 280, 317, 291 ], "page_idx": 45 }, { "type": "text", "text": "用法：", "text_level": 1, "bbox": [ 147, 299, 179, 310 ], "page_idx": 45 }, { "type": "text", "text": "F(\"字段名称\")", "bbox": [ 146, 317, 221, 329 ], "page_idx": 45 }, { "type": "text", "text": "F 动态获取对象字段的值，可以进行运算。", "bbox": [ 146, 335, 366, 347 ], "page_idx": 45 }, { "type": "text", "text": "Django 支持 F() 对象之间以及 F() 对象和常数之间的加减乘除和取余的操作。", "bbox": [ 146, 354, 544, 366 ], "page_idx": 45 }, { "type": "text", "text": "修改操作（update）也可以使用 F() 函数。", "bbox": [ 146, 373, 366, 384 ], "page_idx": 45 }, { "type": "text", "text": "查询工资大于年龄的人：", "bbox": [ 146, 391, 273, 403 ], "page_idx": 45 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 410, 174, 420 ], "page_idx": 45 }, { "type": "text", "text": "from django.db.models import F ", "bbox": [ 146, 428, 322, 439 ], "page_idx": 45 }, { "type": "text", "text": "... ", "bbox": [ 147, 450, 161, 456 ], "page_idx": 45 }, { "type": "text", "text": "book=models.Emp.objects.filter(salary__gt=F(\"age\")).values(\"name\",\"age\") ", "bbox": [ 146, 464, 539, 476 ], "page_idx": 45 }, { "type": "text", "text": "Q() 查询", "bbox": [ 147, 483, 194, 495 ], "page_idx": 45 }, { "type": "text", "text": "使用前要先从 django.db.models 引入 Q:", "bbox": [ 146, 502, 359, 514 ], "page_idx": 45 }, { "type": "text", "text": "from django.db.models import Q ", "bbox": [ 147, 521, 319, 533 ], "page_idx": 45 }, { "type": "text", "text": "用法：", "bbox": [ 147, 539, 179, 551 ], "page_idx": 45 }, { "type": "text", "text": "Q(条件判断) ", "bbox": [ 147, 577, 215, 589 ], "page_idx": 45 }, { "type": "text", "text": "例如：", "bbox": [ 147, 595, 179, 606 ], "page_idx": 45 }, { "type": "text", "text": "Q(title__startswith=\"菜\") ", "bbox": [ 146, 633, 275, 645 ], "page_idx": 45 }, { "type": "text", "text": "之前构造的过滤器里的多个条件的关系都是 and，如果需要执行更复杂的查询（例如 or 语句），就可以使用 Q 。", "bbox": [ 146, 650, 726, 662 ], "page_idx": 45 }, { "type": "text", "text": "Q 对象可以使用 & | ~ （与 或非）操作符进行组合。", "bbox": [ 146, 688, 415, 700 ], "page_idx": 45 }, { "type": "text", "text": "优先级从高到低：~ & |。", "bbox": [ 146, 725, 273, 737 ], "page_idx": 45 }, { "type": "text", "text": "可以混合使用 Q 对象和关键字参数，Q 对象和关键字参数是用\"and\"拼在一起的（即将逗号看成 and ），但是 Q 对象必须位于所有关键字参数的前面。", "bbox": [ 144, 762, 847, 791 ], "page_idx": 45 }, { "type": "text", "text": "查询价格大于 350 或者名称以菜开头的书籍的名称和价格。", "bbox": [ 146, 816, 450, 829 ], "page_idx": 45 }, { "type": "text", "text": "查询出版日期是 2004 或者1999 年，并且书名中包含有\"菜\"的书籍。", "bbox": [ 146, 835, 497, 848 ], "page_idx": 45 }, { "type": "text", "text": "Q 对象和关键字混合使用，Q 对象要在所有关键字的前面:", "bbox": [ 146, 854, 448, 866 ], "page_idx": 45 }, { "type": "text", "text": "总结", "text_level": 1, "bbox": [ 147, 101, 200, 120 ], "page_idx": 46 }, { "type": "text", "text": "books=models.Book.objects ", "bbox": [ 159, 181, 310, 193 ], "page_idx": 46 }, { "type": "text", "text": "print(books,type(books)) ", "bbox": [ 159, 199, 292, 212 ], "page_idx": 46 }, { "type": "text", "text": "TestModel.Book.objects ", "bbox": [ 147, 215, 781, 233 ], "page_idx": 46 }, { "type": "text", "text": "books $=$ models.Book.objects.create(title=\"如来神掌\",price=200,publish=\"功夫出版社\",pub_date=\"2010-10-10\") ", "bbox": [ 147, 237, 727, 250 ], "page_idx": 46 }, { "type": "text", "text": "print(books, type(books)) # Book object (18) ", "bbox": [ 161, 255, 393, 267 ], "page_idx": 46 }, { "type": "text", "text": "Book object (7) ", "bbox": [ 147, 272, 517, 288 ], "page_idx": 46 }, { "type": "text", "text": "books $=$ models.Book.objects.all() ", "bbox": [ 159, 292, 339, 304 ], "page_idx": 46 }, { "type": "text", "text": "print(books,type(books)) ", "bbox": [ 159, 311, 292, 323 ], "page_idx": 46 }, { "type": "text", "text": "]> ", "bbox": [ 147, 329, 727, 341 ], "page_idx": 46 }, { "type": "text", "text": "books $=$ models.Book.objects.first() # 返回所有数据的第一条数据", "bbox": [ 159, 347, 502, 360 ], "page_idx": 46 }, { "type": "text", "text": "print(books, type(books)) ", "bbox": [ 159, 366, 295, 378 ], "page_idx": 46 }, { "type": "text", "text": "Book object (1) ", "bbox": [ 147, 385, 406, 395 ], "page_idx": 46 }, { "type": "text", "text": "等同于", "bbox": [ 147, 404, 186, 414 ], "page_idx": 46 }, { "type": "text", "text": "books $=$ models.Book.objects.filter() # 返回所有数据的第一条数据", "bbox": [ 159, 422, 505, 434 ], "page_idx": 46 }, { "type": "text", "text": "print(books[0], type(books[0])) ", "bbox": [ 159, 439, 321, 451 ], "page_idx": 46 }, { "type": "text", "text": "Book object (1) ", "bbox": [ 147, 458, 406, 470 ], "page_idx": 46 }, { "type": "text", "text": "books $=$ models.Book.objects.values(\"pk\",\"price\") ", "bbox": [ 147, 476, 408, 489 ], "page_idx": 46 }, { "type": "text", "text": "print(books,type(books)) # 得到的是第一条记录的 price 字段的数据", "bbox": [ 159, 495, 510, 508 ], "page_idx": 46 }, { "type": "text", "text": " ", "bbox": [ 147, 514, 821, 526 ], "page_idx": 46 }, { "type": "text", "text": "books $=$ models.Book.objects.values_list(\"price\",\"publish\") ", "bbox": [ 159, 533, 467, 545 ], "page_idx": 46 }, { "type": "text", "text": "print(books,type(books)) ", "bbox": [ 159, 552, 292, 563 ], "page_idx": 46 }, { "type": "text", "text": " ", "bbox": [ 147, 588, 339, 600 ], "page_idx": 46 }, { "type": "text", "text": "1. Book 对象（）", "bbox": [ 147, 607, 423, 619 ], "page_idx": 46 }, { "type": "list", "sub_type": "text", "list_items": [ "含义：Book 是 Django 模型（Model）的一个实例，对应数据库中的一行记录。", "作用：表示单个数据对象，可以访问其字段（如book.title、book.price）。", ". 示例：", ". 特点：" ], "bbox": [ 176, 626, 620, 692 ], "page_idx": 46 }, { "type": "list", "sub_type": "text", "list_items": [ "o 是 TestModel.models.Book 类的实例。", "o 可以直接修改并保存到数据库（book.save()）。" ], "bbox": [ 236, 699, 517, 730 ], "page_idx": 46 }, { "type": "text", "text": "2. Book.objects（）", "bbox": [ 146, 755, 510, 768 ], "page_idx": 46 }, { "type": "list", "sub_type": "text", "list_items": [ "含义：objects 是 Django 模型的默认管理器（Manager），用于执行数据库查询操作。", "作用：提供查询方法（如 all(), filter(), get(), create()），用于操作数据库。", "示例：" ], "bbox": [ 174, 774, 658, 822 ], "page_idx": 46 }, { "type": "list", "sub_type": "text", "list_items": [ "o 是 Manager 类的实例。", "o 不直接返回数据，而是返回QuerySet（查询集）或单个Book。", "o 可以自定义管理器（如 class BookManager(models.Manager)）。" ], "bbox": [ 236, 829, 620, 879 ], "page_idx": 46 }, { "type": "text", "text": "3. QuerySet（）", "bbox": [ 144, 95, 475, 107 ], "page_idx": 47 }, { "type": "list", "sub_type": "text", "list_items": [ "含义：QuerySet 是 Django 查询数据库返回的结果集，可以包含0 个、1 个或多个Book 对象。", "作用：用于链式查询（如过滤、排序、聚合等），但不会立即执行查询（惰性加载）。", "示例：" ], "bbox": [ 174, 112, 702, 161 ], "page_idx": 47 }, { "type": "list", "sub_type": "text", "list_items": [ "o 是惰性的，只有在真正使用时（如遍历、list(queryset)、len(queryset)）才会查询数据库。", "o 可以进一步过滤（filter()）、排序（order_by()）、切片（[:5]）等。", "o 如果只返回一个对象（如 get()），则返回 Book 对象，而不是 QuerySet。" ], "bbox": [ 236, 168, 741, 217 ], "page_idx": 47 }, { "type": "text", "text": "2. 为什么 QuerySet 类型不变，但数据形式不同？", "bbox": [ 144, 224, 406, 236 ], "page_idx": 47 }, { "type": "text", "text": "QuerySet 是 Django 的惰性查询集，它只是生成 SQL 查询的容器，具体返回的数据形式由调用的方法决定：", "bbox": [ 174, 243, 769, 255 ], "page_idx": 47 }, { "type": "list", "sub_type": "text", "list_items": [ "o all() → 返回模型实例。", "o values() → 返回字典。", "o values_list() → 返回元组或单个值。" ], "bbox": [ 236, 261, 457, 310 ], "page_idx": 47 }, { "type": "text", "text": "但 QuerySet 本身的类型始终是 django.db.models.query.QuerySet，因为它代表的是“查询能力”，而不是具体的数据形式。", "bbox": [ 174, 317, 847, 347 ], "page_idx": 47 }, { "type": "text", "text": "3. 如何选择合适的方法？", "text_level": 1, "bbox": [ 146, 372, 275, 384 ], "page_idx": 47 }, { "type": "table", "img_path": "images/325e9eead8dd4eb708f6b6ae0407571b2100f9723cb4103acdda3536fd974f7f.jpg", "table_caption": [], "table_footnote": [], "table_body": "
方法返回的数据形式适用场景
all()QuerySet[Model 实例]需要完整模型对象（如调用 save()、访问关联字段）
values("field1", "field2")QuerySet[dict]只需要部分字段，且希望用字段名访问
values_list("field1", "field2")QuerySet[tuple]只需要字段值，不关心字段名
values_list("field", flat=True)QuerySet[单值]只需要一个字段的列表（如 [1, 2, 3])
", "bbox": [ 144, 398, 848, 592 ], "page_idx": 47 }, { "type": "text", "text": "是的！authors $=$ models.ManyToManyField(\"Author\") 这一行代码会自动创建一个中间表（关联表）来存储多对多关系，但不会直接修改Author 表或当前模型表的结构。以下是详细解释：", "bbox": [ 144, 594, 848, 626 ], "page_idx": 47 }, { "type": "text", "text": "1. 自动创建的中间表", "text_level": 1, "bbox": [ 146, 650, 258, 661 ], "page_idx": 47 }, { "type": "text", "text": "Django 会为你生成一个名为<当前模型表名>_authors 的中间表（例如，如果当前模型是 Book，则表名为book_authors），其结构如下：", "bbox": [ 144, 668, 848, 697 ], "page_idx": 47 }, { "type": "code", "sub_type": "code", "code_caption": [], "code_body": "CREATE TABLE book_authors (\nid INTEGER PRIMARY KEY AUTOINCREMENT, -- SQLite 示例\nbook_id INTEGER NOT NULL, -- 外键指向Book表\nauthor_id INTEGER NOT NULL, -- 外键指向Author表\nFOREIGN KEY (book_id) REFERENCES book(id),\nFOREIGN KEY (author_id) REFERENCES author(id)", "guess_lang": "sql", "bbox": [ 146, 706, 502, 810 ], "page_idx": 47 }, { "type": "text", "text": "); ", "bbox": [ 146, 818, 159, 828 ], "page_idx": 47 }, { "type": "list", "sub_type": "text", "list_items": [ "一 这个表只有 3 个字段：id（主键）、book_id（外键）、author_id（外键）。", "你不需要手动定义这个表，Django 在运行makemigrations 和migrate 时会自动创建。" ], "bbox": [ 174, 835, 662, 866 ], "page_idx": 47 }, { "type": "text", "text": "5. 注意事项", "text_level": 1, "bbox": [ 146, 872, 213, 884 ], "page_idx": 47 }, { "type": "text", "text": "1. 表名规则：", "bbox": [ 176, 891, 263, 902 ], "page_idx": 47 }, { "type": "list", "sub_type": "text", "list_items": [ "o 自动生成的中间表名格式：<当前模型表名>_<字段名 $>$ （如 book_authors）。", "o 如果当前模型表名是 app_book，则中间表名为 app_book_authors。" ], "bbox": [ 236, 93, 673, 124 ], "page_idx": 48 }, { "type": "text", "text": "2. 迁移顺序：", "text_level": 1, "bbox": [ 176, 131, 263, 143 ], "page_idx": 48 }, { "type": "text", "text": "o 确保Author 模型已正确定义并先迁移，否则会报错。", "bbox": [ 236, 149, 544, 161 ], "page_idx": 48 }, { "type": "text", "text": "3. 数据库一致性：", "text_level": 1, "bbox": [ 176, 168, 287, 180 ], "page_idx": 48 }, { "type": "text", "text": "o 不要手动修改中间表，始终通过 Django ORM 操作（如 add()、remove()）。", "bbox": [ 236, 187, 665, 199 ], "page_idx": 48 }, { "type": "text", "text": "总结", "text_level": 1, "bbox": [ 147, 224, 174, 236 ], "page_idx": 48 }, { "type": "text", "text": "行为 结果", "bbox": [ 146, 252, 327, 263 ], "page_idx": 48 }, { "type": "text", "text": "定义 ManyToManyField Django 自动创建中间表", "bbox": [ 146, 288, 426, 300 ], "page_idx": 48 }, { "type": "text", "text": "默认中间表字段 id、<当前模型>_id、<关联模型>_id", "bbox": [ 146, 325, 494, 338 ], "page_idx": 48 }, { "type": "text", "text": "自定义中间表 使用 through= 参数指定模型", "bbox": [ 146, 363, 455, 375 ], "page_idx": 48 }, { "type": "text", "text": "操作关系 通过 add()、remove()、clear() 等方法", "bbox": [ 146, 399, 505, 412 ], "page_idx": 48 }, { "type": "text", "text": "在 Django 中，当你定义一个 ForeignKey 字段时，例如：", "bbox": [ 146, 428, 445, 439 ], "page_idx": 48 }, { "type": "text", "text": "python ", "bbox": [ 147, 447, 186, 458 ], "page_idx": 48 }, { "type": "text", "text": "复制", "bbox": [ 147, 464, 174, 476 ], "page_idx": 48 }, { "type": "text", "text": "下载", "bbox": [ 147, 483, 174, 494 ], "page_idx": 48 }, { "type": "text", "text": "publish $=$ models.ForeignKey(\"Publish\", on_delete=models.CASCADE) ", "bbox": [ 146, 502, 521, 513 ], "page_idx": 48 }, { "type": "text", "text": "Django 实际上会在数据库中创建一个名为publish_id 的列，而不是publish。这是由 Django 的设计机制决定的，原因如下：", "bbox": [ 146, 520, 796, 532 ], "page_idx": 48 }, { "type": "text", "text": "1. 为什么字段名是 publish_id 而不是 publish？", "text_level": 1, "bbox": [ 146, 557, 396, 569 ], "page_idx": 48 }, { "type": "text", "text": "(1) 数据库层面的外键存储", "text_level": 1, "bbox": [ 146, 576, 287, 587 ], "page_idx": 48 }, { "type": "list", "sub_type": "text", "list_items": [ "在关系型数据库（如 MySQL、PostgreSQL、SQLite）中，外键关系是通过存储目标表的主键值来实现的。", ". 例如，如果 Publish 表的主键是 id，那么 Book 表会有一个 publish_id 列，存储的是 Publish 表中某条记录的 id 值。", "1. 为什么列名不同也能关联？", "在关系型数据库（如 MySQL、PostgreSQL、SQLite）中，外键关联的本质是值匹配，而不是列名匹配。只要满足以下条件即可：" ], "bbox": [ 174, 594, 847, 678 ], "page_idx": 48 }, { "type": "text", "text": "", "bbox": [ 176, 687, 189, 696 ], "page_idx": 48 }, { "type": "text", "text": "(2) Django 的 ORM 抽象", "text_level": 1, "bbox": [ 146, 706, 280, 718 ], "page_idx": 48 }, { "type": "list", "sub_type": "text", "list_items": [ "虽然数据库列名是publish_id，但 Django 在Python 模型层面提供了一个名为publish 的属性，用于方便地访问关联对象。", "当你访问 book.publish 时，Django 会自动执行查询，获取对应的 Publish 对象。", "而 book.publish_id 则直接返回数据库中存储的原始外键值（即 Publish 表的 id）。" ], "bbox": [ 174, 724, 850, 772 ], "page_idx": 48 }, { "type": "text", "text": "2. Django 如何实现这种关联？", "text_level": 1, "bbox": [ 146, 780, 307, 791 ], "page_idx": 48 }, { "type": "text", "text": "（1）数据库层面", "text_level": 1, "bbox": [ 154, 799, 240, 810 ], "page_idx": 48 }, { "type": "text", "text": "Django 生成的 SQL 会明确指定外键关联的目标列：", "bbox": [ 176, 816, 473, 828 ], "page_idx": 48 }, { "type": "text", "text": "sql", "bbox": [ 147, 835, 166, 846 ], "page_idx": 48 }, { "type": "text", "text": "复制", "bbox": [ 147, 854, 174, 865 ], "page_idx": 48 }, { "type": "text", "text": "下载", "bbox": [ 147, 873, 174, 883 ], "page_idx": 48 }, { "type": "text", "text": "FOREIGN KEY (publish_id) REFERENCES Publish(id) ", "bbox": [ 146, 891, 436, 902 ], "page_idx": 48 }, { "type": "text", "text": "这里显式声明了 publish_id 关联到 Publish.id，与列名无关。", "bbox": [ 146, 95, 467, 105 ], "page_idx": 49 }, { "type": "text", "text": "（2）ORM 层面", "text_level": 1, "bbox": [ 154, 112, 236, 124 ], "page_idx": 49 }, { "type": "text", "text": "当你访问 book.publish 时，Django 会自动执行类似以下的查询：", "bbox": [ 176, 131, 547, 143 ], "page_idx": 49 }, { "type": "text", "text": "SELECT * FROM Publish WHERE id $=$ book.publish_id; ", "bbox": [ 146, 149, 443, 162 ], "page_idx": 49 }, { "type": "text", "text": "通过 publish_id 的值找到对应的 Publish 记录。", "bbox": [ 146, 168, 398, 181 ], "page_idx": 49 }, { "type": "text", "text": "3. 核心区别对比", "text_level": 1, "bbox": [ 146, 190, 235, 200 ], "page_idx": 49 }, { "type": "table", "img_path": "images/253ad5b303793ce0d4769c6b4c028e01ed1cc3015c9f13cf55d54a3c3ee543c6.jpg", "table_caption": [], "table_footnote": [], "table_body": "
特性.add().create()
作用关联已存在的对象创建新对象并关联
是否创建新对象□否□是
适用关系类型ManyToManyField, ForeignKeyManyToManyField, ForeignKey的反向查询
参数类型对象或ID新对象的字段键值对
返回值无新创建的对象
", "bbox": [ 144, 216, 702, 444 ], "page_idx": 49 }, { "type": "text", "text": "Django Form 组件", "text_level": 1, "bbox": [ 147, 481, 500, 514 ], "page_idx": 49 }, { "type": "text", "text": "Django Form 组件用于对页面进行初始化，生成 HTML 标签，此外还可以对用户提交的数据进行校验（显示错误信息）。", "bbox": [ 146, 527, 769, 539 ], "page_idx": 49 }, { "type": "text", "text": "报错信息显示顺序：", "bbox": [ 146, 565, 250, 576 ], "page_idx": 49 }, { "type": "text", "text": "先显示字段属性中的错误信息，然后再显示局部钩子的错误信息。", "bbox": [ 146, 602, 485, 613 ], "page_idx": 49 }, { "type": "text", "text": "若显示了字段属性的错误信息，就不会显示局部钩子的错误信息。", "bbox": [ 146, 621, 485, 632 ], "page_idx": 49 }, { "type": "text", "text": "若有全局钩子，则全局钩子是等所有的数据都校验完，才开始进行校验，并且全局钩子的错误信息一定会显示。", "bbox": [ 146, 639, 719, 651 ], "page_idx": 49 }, { "type": "text", "text": "Django 用户认证（Auth）组件", "text_level": 1, "bbox": [ 147, 671, 726, 705 ], "page_idx": 49 }, { "type": "text", "text": "Django 用户认证（Auth）组件一般用在用户的登录注册上，用于判断当前的用户是否合法，并跳转到登陆成功或失败页面。", "bbox": [ 144, 719, 784, 731 ], "page_idx": 49 }, { "type": "text", "text": "Django 用户认证（Auth）组件需要导入 auth 模块:", "bbox": [ 146, 738, 413, 749 ], "page_idx": 49 }, { "type": "text", "text": "# 认证模块 ", "bbox": [ 146, 757, 208, 766 ], "page_idx": 49 }, { "type": "text", "text": "from django.contrib import auth ", "bbox": [ 146, 775, 312, 785 ], "page_idx": 49 }, { "type": "text", "text": "# 对应数据库", "bbox": [ 146, 812, 220, 822 ], "page_idx": 49 }, { "type": "text", "text": "from django.contrib.auth.models import User ", "bbox": [ 146, 831, 383, 841 ], "page_idx": 49 }, { "type": "text", "text": "返回值是用户对象。", "bbox": [ 146, 848, 250, 860 ], "page_idx": 49 }, { "type": "text", "text": "创建用户对象的三种方法：", "bbox": [ 146, 868, 285, 879 ], "page_idx": 49 }, { "type": "text", "text": "create()：创建一个普通用户，密码是明文的。", "bbox": [ 176, 885, 447, 897 ], "page_idx": 49 }, { "type": "list", "sub_type": "text", "list_items": [ "create_user()：创建一个普通用户，密码是密文的。", "create_superuser()：创建一个超级用户，密码是密文的，要多传一个邮箱email 参数。" ], "bbox": [ 174, 95, 660, 124 ], "page_idx": 50 }, { "type": "text", "text": "验证用户的用户名和密码使用 authenticate() 方法，从需要auth_user 表中过滤出用户对象。", "bbox": [ 147, 131, 621, 143 ], "page_idx": 50 }, { "type": "text", "text": "使用前要导入：", "bbox": [ 147, 168, 226, 181 ], "page_idx": 50 }, { "type": "text", "text": "from django.contrib import auth ", "bbox": [ 146, 206, 314, 218 ], "page_idx": 50 }, { "type": "text", "text": "参数：", "bbox": [ 147, 225, 179, 235 ], "page_idx": 50 }, { "type": "text", "text": "username：用户名", "bbox": [ 146, 262, 250, 273 ], "page_idx": 50 }, { "type": "text", "text": "password：密码", "bbox": [ 147, 281, 236, 291 ], "page_idx": 50 }, { "type": "text", "text": "返回值：如果验证成功，就返回用户对象，反之，返回 None。", "bbox": [ 146, 299, 468, 310 ], "page_idx": 50 }, { "type": "text", "text": "给验证成功的用户加 session，将 request.user 赋值为用户对象。", "bbox": [ 146, 317, 480, 328 ], "page_idx": 50 }, { "type": "text", "text": "登陆使用 login() 方法。", "bbox": [ 147, 336, 265, 347 ], "page_idx": 50 }, { "type": "text", "text": "使用前要导入：", "bbox": [ 147, 355, 226, 365 ], "page_idx": 50 }, { "type": "text", "text": "from django.contrib import auth ", "bbox": [ 146, 373, 312, 384 ], "page_idx": 50 }, { "type": "text", "text": "参数：", "bbox": [ 147, 392, 179, 401 ], "page_idx": 50 }, { "type": "text", "text": "request：用户对象", "bbox": [ 176, 410, 310, 420 ], "page_idx": 50 }, { "type": "text", "text": "注销用户使用 logout() 方法，需要清空 session 信息，将 request.user 赋值为匿名用户。", "bbox": [ 146, 428, 600, 439 ], "page_idx": 50 }, { "type": "text", "text": "使用前要导入：", "bbox": [ 147, 447, 226, 458 ], "page_idx": 50 }, { "type": "text", "text": "from django.contrib import auth ", "bbox": [ 146, 466, 314, 476 ], "page_idx": 50 }, { "type": "text", "text": "参数：", "bbox": [ 147, 485, 179, 494 ], "page_idx": 50 }, { "type": "text", "text": "request：用户对象", "bbox": [ 176, 502, 310, 514 ], "page_idx": 50 }, { "type": "text", "text": "返回值：None ", "bbox": [ 147, 521, 226, 532 ], "page_idx": 50 }, { "type": "text", "text": "设置装饰器，给需要登录成功后才能访问的页面统一加装饰器。", "bbox": [ 146, 539, 472, 550 ], "page_idx": 50 }, { "type": "text", "text": "使用前要导入：", "bbox": [ 147, 558, 226, 569 ], "page_idx": 50 }, { "type": "text", "text": "from django.contrib.auth.decorators import login_required ", "bbox": [ 146, 577, 450, 588 ], "page_idx": 50 }, { "type": "text", "text": "实例", "text_level": 1, "bbox": [ 147, 596, 174, 606 ], "page_idx": 50 }, { "type": "text", "text": "from django.contrib.auth.decorators import login_required $@$ login_required ", "bbox": [ 146, 614, 547, 625 ], "page_idx": 50 }, { "type": "text", "text": "def index(request): ", "bbox": [ 147, 633, 250, 643 ], "page_idx": 50 }, { "type": "text", "text": "return HttpResponse(\"index 页面。。。\")", "bbox": [ 152, 652, 374, 662 ], "page_idx": 50 }, { "type": "text", "text": "设置从哪个页面访问，登录成功后就返回哪个页面。", "bbox": [ 147, 670, 413, 680 ], "page_idx": 50 }, { "type": "text", "text": "解析：", "text_level": 1, "bbox": [ 147, 688, 179, 699 ], "page_idx": 50 }, { "type": "text", "text": "django 在用户访问页面时，如果用户是未登录的状态，就给用户返回登录页面。", "bbox": [ 146, 707, 559, 717 ], "page_idx": 50 }, { "type": "text", "text": "此时，该登录页面的 URL 后面有参数：next=用户访问的页面的 URL。", "bbox": [ 146, 725, 510, 736 ], "page_idx": 50 }, { "type": "text", "text": "因此，设置在用户登录成功后重定向的 URL 为 next 参数的值。", "bbox": [ 146, 744, 472, 755 ], "page_idx": 50 }, { "type": "text", "text": "但是，若用户一开始就输入登录页面 logi，request.GET.get(\"next\") 就取不到值，所以在后面加or，可以设置自定义返回的页面。", "bbox": [ 146, 762, 810, 772 ], "page_idx": 50 }, { "type": "text", "text": "Django cookie 与 session", "text_level": 1, "bbox": [ 147, 795, 645, 828 ], "page_idx": 50 }, { "type": "text", "text": "Cookie 是存储在客户端计算机上的文本文件，并保留了各种跟踪信息。", "bbox": [ 146, 841, 514, 853 ], "page_idx": 50 }, { "type": "text", "text": "识别返回用户包括三个步骤：", "bbox": [ 147, 860, 297, 872 ], "page_idx": 50 }, { "type": "text", "text": "服务器脚本向浏览器发送一组Cookie。例如：姓名、年龄或识别号码等。", "bbox": [ 176, 879, 584, 890 ], "page_idx": 50 }, { "type": "list", "sub_type": "text", "list_items": [ "浏览器将这些信息存储在本地计算机上，以备将来使用。", "当下一次浏览器向 Web 服务器发送任何请求时，浏览器会把这些 Cookie 信息发送到服务器，服务器将使用这些信息来识别用户。" ], "bbox": [ 174, 95, 847, 142 ], "page_idx": 51 }, { "type": "text", "text": "HTTP 是一种\"无状态\"协议，这意味着每次客户端检索网页时，客户端打开一个单独的连接到 Web 服务器，服务器会自动不保留之前客户端请求的任何记录。", "bbox": [ 144, 149, 847, 180 ], "page_idx": 51 }, { "type": "text", "text": "但是仍然有以下三种方式来维持 Web 客户端和 Web 服务器之间的 session 会话：", "bbox": [ 146, 187, 566, 199 ], "page_idx": 51 }, { "type": "text", "text": "Cookies ", "text_level": 1, "bbox": [ 146, 206, 196, 216 ], "page_idx": 51 }, { "type": "text", "text": "一个 Web 服务器可以分配一个唯一的 session 会话 ID 作为每个 Web 客户端的 cookie，对于客户端的后续请求可以使用接收到的cookie 来识别。", "bbox": [ 144, 224, 845, 254 ], "page_idx": 51 }, { "type": "text", "text": "在 Web 开发中，使用 session 来完成会话跟踪，session 底层依赖 Cookie 技术。", "bbox": [ 146, 261, 564, 273 ], "page_idx": 51 }, { "type": "image", "img_path": "images/9a48075248f18fba9020fddb11e4edfdde6582563e4eadd68f5b3ee2169d2f8d.jpg", "image_caption": [], "image_footnote": [], "bbox": [ 147, 275, 655, 456 ], "page_idx": 51 }, { "type": "text", "text": "Session(保存在服务端的键值对)", "text_level": 1, "bbox": [ 144, 464, 381, 479 ], "page_idx": 51 }, { "type": "text", "text": "服务器在运行时可以为每一个用户的浏览器创建一个其独享的 session 对象，由于 session 为用户浏览器独享，所以用户在访问服务器的 web 资源时，可以把各自的数据放在各自的 session 中，当用户再去访问该服务器中的其它web 资源时，其它web 资源再从用户各自的 session 中取出数据为用户服务。", "bbox": [ 144, 482, 855, 554 ], "page_idx": 51 }, { "type": "image", "img_path": "images/13016cbec949f6ef478321a5634a2c0188ff9b392a433e44d44ca4da2df9e845.jpg", "image_caption": [], "image_footnote": [], "bbox": [ 152, 570, 801, 875 ], "page_idx": 51 }, { "type": "text", "text": "工作原理", "text_level": 1, "bbox": [ 147, 890, 218, 904 ], "page_idx": 51 }, { "type": "list", "sub_type": "text", "list_items": [ "a. 浏览器第一次请求获取登录页面 login。", " b. 浏览器输入账号密码第二次请求，若输入正确，服务器响应浏览器一个 index 页面和一个键为 sessionid，值为随机字符串的 cookie，即 set_cookie (\"sessionid\",随机字符串)。", " c. 服务器内部在 django.session 表中记录一条数据。" ], "bbox": [ 174, 93, 843, 164 ], "page_idx": 52 }, { "type": "text", "text": "django.session 表中有三个字段。", "bbox": [ 144, 168, 379, 183 ], "page_idx": 52 }, { "type": "list", "sub_type": "text", "list_items": [ "o session_key：存的是随机字符串，即响应给浏览器的 cookie 的 sessionid 键对应的值。", "o session_data：存的是用户的信息，即多个 request.session[\"key\"]=value，且是密文。", "o expire_date：存的是该条记录的过期时间（默认 14 天）" ], "bbox": [ 235, 186, 843, 275 ], "page_idx": 52 }, { "type": "text", "text": " d. 浏览器第三次请求其他资源时，携带cookie :{sessionid:随机字符串}，服务器从django.session 表中根据该随机字符串取出该用户的数据，供其使用（即保存状态）。", "bbox": [ 174, 279, 826, 313 ], "page_idx": 52 }, { "type": "text", "text": "注意: django.session 表中保存的是浏览器的信息，而不是每一个用户的信息。 因此， 同一浏览器多个用户请求只保存一条记录（后面覆盖前面）,多个浏览器请求才保存多条记录。", "bbox": [ 144, 316, 842, 349 ], "page_idx": 52 }, { "type": "text", "text": "cookie 弥补了 http 无状态的不足，让服务器知道来的人是\"谁\"，但是 cookie 以文本的形式保存在浏览器端，安全性较差，且最大只支持 4096 字节，所以只通过 cookie 识别不同的用户，然后，在对应的 session 里保存私密的信息以及超过 4096 字节的文本。", "bbox": [ 144, 353, 836, 405 ], "page_idx": 52 }, { "type": "text", "text": "session 设置：", "bbox": [ 144, 409, 243, 423 ], "page_idx": 52 }, { "type": "text", "text": "request.session[\"key\"] $=$ value ", "bbox": [ 144, 426, 356, 442 ], "page_idx": 52 }, { "type": "text", "text": "执行步骤：", "bbox": [ 144, 445, 226, 460 ], "page_idx": 52 }, { "type": "list", "sub_type": "text", "list_items": [ "a. 生成随机字符串 ", " b. 把随机字符串和设置的键值对保存到 django_session 表的 session_key 和 session_data里", " c. 设置 cookie：set_cookie(\"sessionid\",随机字符串) 响应给浏览器" ], "bbox": [ 174, 464, 836, 535 ], "page_idx": 52 }, { "type": "text", "text": "session 获取：", "bbox": [ 144, 539, 243, 552 ], "page_idx": 52 }, { "type": "text", "text": "request.session.get('key') ", "bbox": [ 144, 557, 319, 571 ], "page_idx": 52 }, { "type": "text", "text": "执行步骤：", "bbox": [ 144, 575, 226, 590 ], "page_idx": 52 }, { "type": "list", "sub_type": "text", "list_items": [ " a. 从 cookie 中获取 sessionid 键的值，即随机字符串。", " b. 根据随机字符串从 django_session 表过滤出记录。", " c. 取出 session_data 字段的数据。" ], "bbox": [ 174, 594, 591, 646 ], "page_idx": 52 }, { "type": "text", "text": "session 删除，删除整条记录（包括 session_key、session_data、expire_date 三个字段）：", "bbox": [ 144, 649, 781, 665 ], "page_idx": 52 }, { "type": "text", "text": "request.session.flush() ", "bbox": [ 144, 668, 300, 683 ], "page_idx": 52 }, { "type": "text", "text": "删除 session_data 里的其中一组键值对：", "bbox": [ 144, 686, 435, 702 ], "page_idx": 52 }, { "type": "text", "text": "del request.session[\"key\"] ", "bbox": [ 144, 705, 326, 720 ], "page_idx": 52 }, { "type": "text", "text": "执行步骤：", "bbox": [ 144, 722, 226, 738 ], "page_idx": 52 }, { "type": "list", "sub_type": "text", "list_items": [ " a. 从 cookie 中获取 sessionid 键的值，即随机字符串", " b. 根据随机字符串从 django_session 表过滤出记录", " c. 删除过滤出来的记录" ], "bbox": [ 174, 741, 584, 793 ], "page_idx": 52 }, { "type": "text", "text": "Django 中间件", "text_level": 1, "bbox": [ 144, 797, 258, 813 ], "page_idx": 52 }, { "type": "text", "text": "Django 中间件是修改 Django request 或者 response 对象的钩子，可以理解为是介于 HttpRequest与 HttpResponse 处理之间的一道处理过程。", "bbox": [ 144, 816, 838, 850 ], "page_idx": 52 }, { "type": "text", "text": "浏览器从请求到响应的过程中，Django 需要通过很多中间件来处理，可以看如下图所示：", "bbox": [ 144, 853, 800, 869 ], "page_idx": 52 }, { "type": "image", "img_path": "images/eff2575789a078e5215193fc6d91fb3d590196cf4b9a4bc9c76cfb08807856a7.jpg", "image_caption": [], "image_footnote": [], "bbox": [ 147, 95, 815, 363 ], "page_idx": 53 }, { "type": "text", "text": "Django 中间件作用：", "bbox": [ 146, 390, 295, 405 ], "page_idx": 53 }, { "type": "list", "sub_type": "text", "list_items": [ " 修改请求，即传送到 view 中的 HttpRequest 对象。", " 修改响应，即 view 返回的 HttpResponse 对象。" ], "bbox": [ 176, 409, 569, 443 ], "page_idx": 53 }, { "type": "text", "text": "中间件组件配置在 settings.py 文件的 MIDDLEWARE 选项列表中。", "bbox": [ 144, 445, 630, 461 ], "page_idx": 53 }, { "type": "text", "text": "配置中的每个字符串选项都是一个类，也就是一个中间件。", "bbox": [ 146, 464, 576, 479 ], "page_idx": 53 }, { "type": "text", "text": "自定义中间件", "bbox": [ 147, 482, 253, 497 ], "page_idx": 53 }, { "type": "text", "text": "中间件可以定义四个方法，分别是：", "bbox": [ 146, 501, 410, 516 ], "page_idx": 53 }, { "type": "text", "text": "process_request(self,request) ", "bbox": [ 144, 539, 347, 552 ], "page_idx": 53 }, { "type": "text", "text": "process_view(self, request, view_func, view_args, view_kwargs) ", "bbox": [ 146, 557, 589, 571 ], "page_idx": 53 }, { "type": "text", "text": "process_exception(self, request, exception) ", "bbox": [ 147, 576, 440, 590 ], "page_idx": 53 }, { "type": "text", "text": "process_response(self, request, response) ", "bbox": [ 147, 595, 428, 609 ], "page_idx": 53 } ]