写一个简单的项目小例子来了解Django中的O/RM操作

前戏

创建app

#在Django项目根目录下执行

python3 manage.py startapp [app name]

配置数据库连接信息

DATABASES = {

    'default': {

        'ENGINE': 'django.db.backends.mysql',  # 连接的数据库类型

        'HOST': '127.0.0.1',  # 连接数据库的地址

        'PORT': 3306,  # 端口

        'NAME': "testdb",  # 数据库名称

        'USER': 'root',  # 用户

        'PASSWORD': 'root'  # 密码

    }

}

/[project name]/settings.py->DATABASES节

让Django用pymysql来代替默认的MySQLdb

import pymysql

pymysql.install_as_MySQLdb()

/[project name]/__init__.py

让项目'知道'APP

INSTALLED_APPS = [

    'django.contrib.admin',

    'django.contrib.auth',

    'django.contrib.contenttypes',

    'django.contrib.sessions',

    'django.contrib.messages',

    'django.contrib.staticfiles',

    'login_app.apps.LoginAppConfig'

]

/[project name]/settings.py->INSTALLED_APPS节

表关系

代码

创建模型

在app下面的models.py文件中定义类,这些类必须继承models.Model

 from django.db import models

 class Press(models.Model):

     '''

     出版社

     '''

     id = models.AutoField(primary_key=True)

     name = models.CharField(max_length=50, unique=True)

 class Book(models.Model):

     '''

     书籍

     '''

     id = models.AutoField(primary_key=True)

     name = models.CharField(max_length=50, unique=True)

     press = models.ForeignKey(Press)

 class Author(models.Model):

     '''

     作者

     '''

     id = models.AutoField(primary_key=True)

     name = models.CharField(max_length=50, unique=True)

     book = models.ManyToManyField(Book)

/[app name]/models.py

执行命令

python3 manage.py makemigrations # 对比模型和db的差异,记录下将要发生的变更
python3 manage.py migrate # 将记录的变更在数据库中执行

CRUD操作

  • 出版社(一对多)

     from django.shortcuts import render, HttpResponse, redirect
    
 from bookapp import models

 def add(request):
    
     '''
    
     添加
    
     '''
    
     if request.method == 'POST':
    
         name = request.POST.get('name')
    
         models.Press.objects.create(name=name).save()
    
         return redirect('/list_press/')
    
     return render(request, 'press/add.html')

 def list(request):
    
     '''
    
     列表
    
     '''
    
     all_list = models.Press.objects.all()
    
     return render(request, 'press/list.html', {'list': all_list})

 def edit(request):
    
     '''
    
     编辑
    
     '''
    
     if request.method == 'POST':
    
         id = request.POST.get('id')
    
         name = request.POST.get('name')
    
         obj = models.Press.objects.get(id=id)
    
         obj.name = name
    
         obj.save()
    
         return redirect('/list_press/')
    
     id = request.GET.get('id')
    
     obj = models.Press.objects.get(id=id)
    
     return render(request, 'press/edit.html', {'press': obj})

 def delete(request):
    
     '''
    
     删除
    
     '''
    
     id = request.GET.get('id')
    
     models.Press.objects.get(id=id).delete()
    
     return redirect('/list_press/')

    /[app name]/service/press.py

     <!DOCTYPE html>
    
 <html lang="en">
    
 <head>
    
     <meta charset="UTF-8">
    
     <title>添加出版社</title>
    
 </head>
    
 <body>
    
 <form action="/add_press/" method="post">
    
     <p>名称:<input name="name" type="text"></p>
    
     <p><input type="submit" value="提交"></p>
    
 </form>
    
 </body>
    
 </html>

    /templates/press/add.html 添加出版社页

     <!DOCTYPE html>
    
 <html lang="en">
    
 <head>
    
     <meta charset="UTF-8">
    
     <title>出版社列表</title>
    
 </head>
    
 <body>
    
 <a href="/add_press/">添加</a>
    
 <table border="1" style="border-collapse:collapse;">
    
     <tr>
    
         <td>序号</td>
    
         <td>名称</td>
    
         <td>拥有书籍</td>
    
         <td colspan="2">操作</td>
    
     </tr>
    
     {% for press in list %}
    
         <tr>
    
             <td>{{ forloop.counter }}</td>
    
             <td>{{ press.name }}</td>
    
             <td>{% for book in press.book_set.all %}
    
                 {% if forloop.counter == press.book_set.all.count %}
    
                     {{ book.name }}
    
                 {% else %}
    
                     {{ book.name }},
    
                 {% endif %}
    
             {% endfor %}</td>
    
             <td><a href="/edit_press/?id={{ press.id }}">编辑</a></td>
    
             <td><a href="/del_press/?id={{ press.id }}">删除</a></td>
    
         </tr>
    
     {% endfor %}
    
 </table>
    
 </body>
    
 </html>

    /templates/press/list.html 出版社列表页

     <!DOCTYPE html>
    
 <html lang="en">
    
 <head>
    
     <meta charset="UTF-8">
    
     <title>修改出版社</title>
    
 </head>
    
 <body>
    
 <form action="/edit_press/" method="post">
    
     <input type="hidden" name="id" value="{{ press.id }}">
    
     <p>名称:<input name="name" type="text" value="{{ press.name }}"></p>
    
     <p><input type="submit" value="提交"></p>
    
 </form>
    
 </body>
    
 </html>

    /templates/press/edit.html 编辑出版社页

  • 书籍(多对一&多对多)

     from django.shortcuts import render, HttpResponse, redirect
    
 from bookapp import models

 def add(request):
    
     '''
    
     添加
    
     '''
    
     if request.method == 'POST':
    
         press_id = request.POST.get('press_id')
    
         name = request.POST.get('name')
    
         models.Book.objects.create(name=name, press_id=press_id).save()
    
         return redirect('/list_book/')
    
     press_list = models.Press.objects.all()
    
     return render(request, 'book/add.html', {'press_list': press_list})

 def list(request):
    
     '''
    
     列表
    
     '''
    
     all_list = models.Book.objects.all()
    
     return render(request, 'book/list.html', {'list': all_list})

 def edit(request):
    
     '''
    
     编辑
    
     '''
    
     if request.method == 'POST':
    
         id = request.POST.get('id')
    
         name = request.POST.get('name')
    
         press_id = request.POST.get('press_id')
    
         obj = models.Book.objects.get(id=id)
    
         obj.name = name
    
         obj.press_id = press_id
    
         obj.save()
    
         return redirect('/list_book/')
    
     id = request.GET.get('id')
    
     obj = models.Book.objects.get(id=id)
    
     press_list = models.Press.objects.all()
    
     return render(request, 'book/edit.html', {'book': obj, 'press_list': press_list})

 def delete(request):
    
     '''
    
     删除
    
     '''
    
     id = request.GET.get('id')
    
     models.Book.objects.get(id=id).delete()
    
     return redirect('/list_book/')

    /[app name]/service/book.py

     <!DOCTYPE html>
    
 <html lang="en">
    
 <head>
    
     <meta charset="UTF-8">
    
     <title>添加书籍</title>
    
 </head>
    
 <body>
    
 <form action="/add_book/" method="post">
    
     <p>名称:<input name="name" type="text"></p>
    
     <p>出版社: <select name="press_id" >
    
         {% for press in press_list %}
    
         <option value="{{ press.id }}">{{ press.name }}</option>
    
         {% endfor %}
    
     </select></p>
    
     <p><input type="submit" value="提交"></p>
    
 </form>
    
 </body>
    
 </html>

    /templates/book/add.html 添加书籍页

     <!DOCTYPE html>
    
 <html lang="en">
    
 <head>
    
     <meta charset="UTF-8">
    
     <title>书籍列表</title>
    
 </head>
    
 <body>
    
 <a href="/add_book/">添加</a>
    
 <table border="1" style="border-collapse:collapse;">
    
     <tr>
    
         <td>序号</td>
    
         <td>名称</td>
    
         <td>出版社</td>
    
         <td colspan="2">操作</td>
    
     </tr>
    
     {% for book in list %}
    
         <tr>
    
             <td>{{ forloop.counter }}</td>
    
             <td>{{ book.name }}</td>
    
             <td>{{ book.press.name }}</td>
    
             <td><a href="/edit_book/?id={{ book.id }}">编辑</a></td>
    
             <td><a href="/del_book/?id={{ book.id }}">删除</a></td>
    
         </tr>
    
     {% endfor %}
    
 </table>
    
 </body>
    
 </html>

    /templates/book/list.html 书籍列表页

     <!DOCTYPE html>
    
 <html lang="en">
    
 <head>
    
     <meta charset="UTF-8">
    
     <title>修改书籍</title>
    
 </head>
    
 <body>
    
 <form action="/edit_book/" method="post">
    
     <input type="hidden" name="id" value="{{ book.id }}">
    
     <p>名称:<input name="name" type="text" value="{{ book.name }}"></p>
    
     <p>出版社:
    
         <select name="press_id">
    
             {% for press in press_list %}
    
                 {% if book.press.id == press.id %}
    
                     <option selected value="{{ press.id }}">{{ press.name }}</option>
    
                 {% else %}
    
                     <option value="{{ press.id }}">{{ press.name }}</option>
    
                 {% endif %}
    
             {% endfor %}
    
         </select>
    
     </p>
    
     <p><input type="submit" value="提交"></p>
    
 </form>
    
 </body>
    
 </html>

    /templates/book/edit.html 编辑书籍页

  • 作者(多对多)

     from django.shortcuts import render, HttpResponse, redirect
    
 from bookapp import models

 def add(request):
    
     '''
    
     添加
    
     '''
    
     if request.method == 'POST':
    
         book_id_list = request.POST.getlist('book_id_list')
    
         print(book_id_list)
    
         name = request.POST.get('name')
    
         author = models.Author.objects.create(name=name)
    
         author.book = book_id_list
    
         author.save()
    
         return redirect('/list_author/')
    
     book_list = models.Book.objects.all()
    
     return render(request, 'author/add.html', {'book_list': book_list})

 def list(request):
    
     '''
    
     列表
    
     '''
    
     all_list = models.Author.objects.all()
    
     return render(request, 'author/list.html', {'list': all_list})

 def edit(request):
    
     '''
    
     编辑
    
     '''
    
     if request.method == 'POST':
    
         id = request.POST.get('id')
    
         name = request.POST.get('name')
    
         book_id_list = request.POST.getlist('book_id_list')
    
         obj = models.Author.objects.get(id=id)
    
         obj.name = name
    
         obj.book = book_id_list
    
         obj.save()
    
         return redirect('/list_author/')
    
     id = request.GET.get('id')
    
     obj = models.Author.objects.get(id=id)
    
     book_list = models.Book.objects.all()
    
     return render(request, 'author/edit.html', {'author': obj, 'book_list': book_list})

 def delete(request):
    
     '''
    
     删除
    
     '''
    
     id = request.GET.get('id')
    
     models.Author.objects.get(id=id).delete()
    
     return redirect('/list_author/')

    /[app name]/service/author.py

     <!DOCTYPE html>
    
 <html lang="en">
    
 <head>
    
     <meta charset="UTF-8">
    
     <title>添加作者</title>
    
 </head>
    
 <body>
    
 <form action="/add_author/" method="post">
    
     <p>姓名:<input name="name" type="text"></p>
    
     <p>拥有书籍: <select name="book_id_list" multiple>
    
         {% for book in book_list %}
    
             <option value="{{ book.id }}">{{ book.name }}</option>
    
         {% endfor %}
    
     </select></p>
    
     <p><input type="submit" value="提交"></p>
    
 </form>
    
 </body>
    
 </html>

    /templates/author/add.html 添加作者页

     <!DOCTYPE html>
    
 <html lang="en">
    
 <head>
    
     <meta charset="UTF-8">
    
     <title>作者列表</title>
    
 </head>
    
 <body>
    
 <a href="/add_author/">添加</a>
    
 <table border="1" style="border-collapse:collapse;">
    
     <tr>
    
         <td>序号</td>
    
         <td>姓名</td>
    
         <td>拥有书籍</td>
    
         <td colspan="2">操作</td>
    
     </tr>
    
     {% for author in list %}
    
         <tr>
    
             <td>{{ forloop.counter }}</td>
    
             <td>{{ author.name }}</td>
    
             <td>{% for book in author.book.all %}
    
                 {% if forloop.counter == author.book.count %}
    
                     {{ book.name }}
    
                 {% else %}
    
                     {{ book.name }},
    
                 {% endif %}
    
             {% endfor %}
    
             </td>
    
             <td><a href="/edit_author/?id={{ author.id }}">编辑</a></td>
    
             <td><a href="/del_author/?id={{ author.id }}">删除</a></td>
    
         </tr>
    
     {% endfor %}
    
 </table>
    
 </body>
    
 </html>

    /templates/author/list.html 作者列表页

     <!DOCTYPE html>
    
 <html lang="en">
    
 <head>
    
     <meta charset="UTF-8">
    
     <title>修改作者</title>
    
 </head>
    
 <body>
    
 <form action="/edit_author/" method="post">
    
     <input type="hidden" name="id" value="{{ author.id }}">
    
     <p>姓名:<input name="name" type="text" value="{{ author.name }}"></p>
    
     <p>拥有书籍:
    
         <select name="book_id_list" multiple>
    
             {% for book in book_list %}
    
                 {% if book in author.book.all %}
    
                     <option selected value="{{ book.id }}">{{ book.name }}</option>
    
                 {% else %}
    
                     <option value="{{ book.id }}">{{ book.name }}</option>
    
                 {% endif %}
    
             {% endfor %}
    
         </select>
    
     </p>
    
     <p><input type="submit" value="提交"></p>
    
 </form>
    
 </body>
    
 </html>

    /templates/author/edit.html 编辑作者页

配置路由

 from django.shortcuts import render, HttpResponse, redirect

 from bookapp.service import press

 from bookapp.service import book

 from bookapp.service import author

/[app name]/views.py

 from django.conf.urls import url

 from django.contrib import admin

 from django.conf.urls import url

 from bookapp import views

 urlpatterns = [

     url(r'^add_press/', views.press.add),

     url(r'^list_press/', views.press.list),

     url(r'^edit_press/', views.press.edit),

     url(r'^del_press/', views.press.delete),

     url(r'^add_book/', views.book.add),

     url(r'^list_book/', views.book.list),

     url(r'^edit_book/', views.book.edit),

     url(r'^del_book/', views.book.delete),

     url(r'^add_author/', views.author.add),

     url(r'^list_author/', views.author.list),

     url(r'^edit_author/', views.author.edit),

     url(r'^del_author/', views.author.delete),

 ]

/[project name]/urls.py

点击下载完整示例

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