python框架之Django(2)-简单的CRUD

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

 1 from django.db import models
 2 
 3 
 4 class Press(models.Model):
 5     '''
 6     出版社
 7     '''
 8     id = models.AutoField(primary_key=True)
 9     name = models.CharField(max_length=50, unique=True)
10 
11 
12 class Book(models.Model):
13     '''
14     书籍
15     '''
16     id = models.AutoField(primary_key=True)
17     name = models.CharField(max_length=50, unique=True)
18     press = models.ForeignKey(Press)
19 
20 
21 class Author(models.Model):
22     '''
23     作者
24     '''
25     id = models.AutoField(primary_key=True)
26     name = models.CharField(max_length=50, unique=True)
27     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)

 1 from django.shortcuts import render, HttpResponse, redirect
 2 from bookapp import models
 3 
 4 def add(request):
 5     '''
 6     添加
 7     '''
 8     if request.method == 'POST':
 9         name = request.POST.get('name')
10         models.Press.objects.create(name=name).save()
11         return redirect('/list_press/')
12     return render(request, 'press/add.html')
13 
14 
15 def list(request):
16     '''
17     列表
18     '''
19     all_list = models.Press.objects.all()
20     return render(request, 'press/list.html', {'list': all_list})
21 
22 
23 def edit(request):
24     '''
25     编辑
26     '''
27     if request.method == 'POST':
28         id = request.POST.get('id')
29         name = request.POST.get('name')
30         obj = models.Press.objects.get(id=id)
31         obj.name = name
32         obj.save()
33         return redirect('/list_press/')
34     id = request.GET.get('id')
35     obj = models.Press.objects.get(id=id)
36     return render(request, 'press/edit.html', {'press': obj})
37 
38 
39 def delete(request):
40     '''
41     删除
42     '''
43     id = request.GET.get('id')
44     models.Press.objects.get(id=id).delete()
45     return redirect('/list_press/')

/[app name]/service/press.py

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>添加出版社</title>
 6 </head>
 7 <body>
 8 <form action="/add_press/" method="post">
 9     <p>名称:<input name="name" type="text"></p>
10     <p><input type="submit" value="提交"></p>
11 </form>
12 </body>
13 </html>

/templates/press/add.html 添加出版社页

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>出版社列表</title>
 6 </head>
 7 <body>
 8 <a href="/add_press/">添加</a>
 9 <table border="1" style="border-collapse:collapse;">
10     <tr>
11         <td>序号</td>
12         <td>名称</td>
13         <td>拥有书籍</td>
14         <td colspan="2">操作</td>
15     </tr>
16     {% for press in list %}
17         <tr>
18             <td>{{ forloop.counter }}</td>
19             <td>{{ press.name }}</td>
20             <td>{% for book in press.book_set.all %}
21                 {% if forloop.counter == press.book_set.all.count %}
22                     {{ book.name }}
23                 {% else %}
24                     {{ book.name }},
25                 {% endif %}
26             {% endfor %}</td>
27             <td><a href="/edit_press/?id={{ press.id }}">编辑</a></td>
28             <td><a href="/del_press/?id={{ press.id }}">删除</a></td>
29         </tr>
30     {% endfor %}
31 </table>
32 </body>
33 </html>

/templates/press/list.html 出版社列表页

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>修改出版社</title>
 6 </head>
 7 <body>
 8 <form action="/edit_press/" method="post">
 9     <input type="hidden" name="id" value="{{ press.id }}">
10     <p>名称:<input name="name" type="text" value="{{ press.name }}"></p>
11     <p><input type="submit" value="提交"></p>
12 </form>
13 </body>
14 </html>

/templates/press/edit.html 编辑出版社页

书籍(多对一&多对多)

 1 from django.shortcuts import render, HttpResponse, redirect
 2 from bookapp import models
 3 
 4 
 5 def add(request):
 6     '''
 7     添加
 8     '''
 9     if request.method == 'POST':
10         press_id = request.POST.get('press_id')
11         name = request.POST.get('name')
12         models.Book.objects.create(name=name, press_id=press_id).save()
13         return redirect('/list_book/')
14     press_list = models.Press.objects.all()
15     return render(request, 'book/add.html', {'press_list': press_list})
16 
17 
18 def list(request):
19     '''
20     列表
21     '''
22     all_list = models.Book.objects.all()
23     return render(request, 'book/list.html', {'list': all_list})
24 
25 
26 def edit(request):
27     '''
28     编辑
29     '''
30     if request.method == 'POST':
31         id = request.POST.get('id')
32         name = request.POST.get('name')
33         press_id = request.POST.get('press_id')
34         obj = models.Book.objects.get(id=id)
35         obj.name = name
36         obj.press_id = press_id
37         obj.save()
38         return redirect('/list_book/')
39     id = request.GET.get('id')
40     obj = models.Book.objects.get(id=id)
41     press_list = models.Press.objects.all()
42     return render(request, 'book/edit.html', {'book': obj, 'press_list': press_list})
43 
44 
45 def delete(request):
46     '''
47     删除
48     '''
49     id = request.GET.get('id')
50     models.Book.objects.get(id=id).delete()
51     return redirect('/list_book/')

/[app name]/service/book.py

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>添加书籍</title>
 6 </head>
 7 <body>
 8 <form action="/add_book/" method="post">
 9     <p>名称:<input name="name" type="text"></p>
10     <p>出版社: <select name="press_id" >
11         {% for press in press_list %}
12         <option value="{{ press.id }}">{{ press.name }}</option>
13         {% endfor %}
14     </select></p>
15     <p><input type="submit" value="提交"></p>
16 </form>
17 </body>
18 </html>

/templates/book/add.html 添加书籍页

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>书籍列表</title>
 6 </head>
 7 <body>
 8 <a href="/add_book/">添加</a>
 9 <table border="1" style="border-collapse:collapse;">
10     <tr>
11         <td>序号</td>
12         <td>名称</td>
13         <td>出版社</td>
14         <td colspan="2">操作</td>
15     </tr>
16     {% for book in list %}
17         <tr>
18             <td>{{ forloop.counter }}</td>
19             <td>{{ book.name }}</td>
20             <td>{{ book.press.name }}</td>
21             <td><a href="/edit_book/?id={{ book.id }}">编辑</a></td>
22             <td><a href="/del_book/?id={{ book.id }}">删除</a></td>
23         </tr>
24     {% endfor %}
25 </table>
26 </body>
27 </html>

/templates/book/list.html 书籍列表页

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>修改书籍</title>
 6 </head>
 7 <body>
 8 <form action="/edit_book/" method="post">
 9     <input type="hidden" name="id" value="{{ book.id }}">
10     <p>名称:<input name="name" type="text" value="{{ book.name }}"></p>
11     <p>出版社:
12         <select name="press_id">
13             {% for press in press_list %}
14                 {% if book.press.id == press.id %}
15                     <option selected value="{{ press.id }}">{{ press.name }}</option>
16                 {% else %}
17                     <option value="{{ press.id }}">{{ press.name }}</option>
18                 {% endif %}
19             {% endfor %}
20         </select>
21     </p>
22     <p><input type="submit" value="提交"></p>
23 </form>
24 </body>
25 </html>

/templates/book/edit.html 编辑书籍页

作者(多对多)

 1 from django.shortcuts import render, HttpResponse, redirect
 2 from bookapp import models
 3 
 4 
 5 def add(request):
 6     '''
 7     添加
 8     '''
 9     if request.method == 'POST':
10         book_id_list = request.POST.getlist('book_id_list')
11         print(book_id_list)
12         name = request.POST.get('name')
13         author = models.Author.objects.create(name=name)
14         author.book = book_id_list
15         author.save()
16         return redirect('/list_author/')
17     book_list = models.Book.objects.all()
18     return render(request, 'author/add.html', {'book_list': book_list})
19 
20 
21 def list(request):
22     '''
23     列表
24     '''
25     all_list = models.Author.objects.all()
26     return render(request, 'author/list.html', {'list': all_list})
27 
28 
29 def edit(request):
30     '''
31     编辑
32     '''
33     if request.method == 'POST':
34         id = request.POST.get('id')
35         name = request.POST.get('name')
36         book_id_list = request.POST.getlist('book_id_list')
37         obj = models.Author.objects.get(id=id)
38         obj.name = name
39         obj.book = book_id_list
40         obj.save()
41         return redirect('/list_author/')
42     id = request.GET.get('id')
43     obj = models.Author.objects.get(id=id)
44     book_list = models.Book.objects.all()
45     return render(request, 'author/edit.html', {'author': obj, 'book_list': book_list})
46 
47 
48 def delete(request):
49     '''
50     删除
51     '''
52     id = request.GET.get('id')
53     models.Author.objects.get(id=id).delete()
54     return redirect('/list_author/')

/[app name]/service/author.py

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>添加作者</title>
 6 </head>
 7 <body>
 8 <form action="/add_author/" method="post">
 9     <p>姓名:<input name="name" type="text"></p>
10     <p>拥有书籍: <select name="book_id_list" multiple>
11         {% for book in book_list %}
12             <option value="{{ book.id }}">{{ book.name }}</option>
13         {% endfor %}
14     </select></p>
15     <p><input type="submit" value="提交"></p>
16 </form>
17 </body>
18 </html>

/templates/author/add.html 添加作者页

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>作者列表</title>
 6 </head>
 7 <body>
 8 <a href="/add_author/">添加</a>
 9 <table border="1" style="border-collapse:collapse;">
10     <tr>
11         <td>序号</td>
12         <td>姓名</td>
13         <td>拥有书籍</td>
14         <td colspan="2">操作</td>
15     </tr>
16     {% for author in list %}
17         <tr>
18             <td>{{ forloop.counter }}</td>
19             <td>{{ author.name }}</td>
20             <td>{% for book in author.book.all %}
21                 {% if forloop.counter == author.book.count %}
22                     {{ book.name }}
23                 {% else %}
24                     {{ book.name }},
25                 {% endif %}
26             {% endfor %}
27             </td>
28             <td><a href="/edit_author/?id={{ author.id }}">编辑</a></td>
29             <td><a href="/del_author/?id={{ author.id }}">删除</a></td>
30         </tr>
31     {% endfor %}
32 </table>
33 </body>
34 </html>

/templates/author/list.html 作者列表页

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>修改作者</title>
 6 </head>
 7 <body>
 8 <form action="/edit_author/" method="post">
 9     <input type="hidden" name="id" value="{{ author.id }}">
10     <p>姓名:<input name="name" type="text" value="{{ author.name }}"></p>
11     <p>拥有书籍:
12         <select name="book_id_list" multiple>
13             {% for book in book_list %}
14                 {% if book in author.book.all %}
15                     <option selected value="{{ book.id }}">{{ book.name }}</option>
16                 {% else %}
17                     <option value="{{ book.id }}">{{ book.name }}</option>
18                 {% endif %}
19             {% endfor %}
20         </select>
21     </p>
22     <p><input type="submit" value="提交"></p>
23 </form>
24 </body>
25 </html>

/templates/author/edit.html 编辑作者页

配置路由

1 from django.shortcuts import render, HttpResponse, redirect
2 from bookapp.service import press
3 from bookapp.service import book
4 from bookapp.service import author

/[app name]/views.py

 1 from django.conf.urls import url
 2 from django.contrib import admin
 3 
 4 from django.conf.urls import url
 5 from bookapp import views
 6 urlpatterns = [
 7     url(r'^add_press/', views.press.add),
 8     url(r'^list_press/', views.press.list),
 9     url(r'^edit_press/', views.press.edit),
10     url(r'^del_press/', views.press.delete),
11     url(r'^add_book/', views.book.add),
12     url(r'^list_book/', views.book.list),
13     url(r'^edit_book/', views.book.edit),
14     url(r'^del_book/', views.book.delete),
15     url(r'^add_author/', views.author.add),
16     url(r'^list_author/', views.author.list),
17     url(r'^edit_author/', views.author.edit),
18     url(r'^del_author/', views.author.delete),
19 ]

/[project name]/urls.py

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