Python - Django - ORM 实例 - Python

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准备工作：

首先创建一个名为 Py_Django 的数据库

新建项目，名为 mysite0

创建完成后需要进行几项配置

mysite0/settings.py 下

首先是 html 文件相关

其次是数据库配置

最后注释掉 CSRF 的代码

在 mysite0/__init__.py 中添加以下代码

import pymysql

pymysql.install_as_MySQLdb()

app01/models.py 中写上创建表的类

from django.db import models

# Create your models here.

# 出版社

class Publisher(models.Model):

    id = models.AutoField(primary_key=True)  # 自增的 id 主键

    # 创建一个 varchar(64) 的唯一的不为空的字段

    name = models.CharField(max_length=64, null=False, unique=True)

执行一下两条命令来创建表

python manage.py makemigrations

python manage.py migrate

连接数据库，创建三条数据

展示出版社列表：

publisher_list.html：

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>出版社列表</title>

</head>

<body>

<table border="1">

    <thead>

    <tr>

        <th>序号</th>

        <th>ID</th>

        <th>出版社名称</th>

    </tr>

    </thead>

    <tbody>

    {% for publisher in publisher_list %}

        <tr>

        <td>{{ forloop.counter }}</td>

        <td>{{ publisher.id }}</td>

        <td>{{ publisher.name }}</td>

        </tr>

    {% endfor %}

    </tbody>

</table>

</body>

</html>

第几次循环，forloop.counter 的值就是多少

app01/views.py 中 publisher_list 函数：

from django.shortcuts import render

from app01 import models

# Create your views here.

# 展示出版社列表

def publisher_list(request):

    # 去数据库查出所有的出版社，填充到 html 中，返回给用户

    ret = models.Publisher.objects.all().order_by("id")  # order_by("id") 通过 id 进行排序

    return render(request, "publisher_list.html", {"publisher_list": ret})

在 mysite0/urls.py 中添加对应关系

from django.conf.urls import url

from django.contrib import admin

from app01 import views

urlpatterns = [

    url(r'^admin/', admin.site.urls),

    url(r'^publisher_list/', views.publisher_list),

]

运行结果：

添加出版社：

修改 publisher_list.html:

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>出版社列表</title>

</head>

<body>

<table border="1">

    <thead>

    <tr>

        <th>序号</th>

        <th>ID</th>

        <th>出版社名称</th>

    </tr>

    </thead>

    <tbody>

    {% for publisher in publisher_list %}

        <tr>

        <td>{{ forloop.counter }}</td>

        <td>{{ publisher.id }}</td>

        <td>{{ publisher.name }}</td>

        </tr>

    {% endfor %}

    </tbody>

</table>

<a href="/add_publisher/">添加新的出版社</a>

</body>

</html>

创建 add_publisher.html：

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>添加出版社</title>

</head>

<body>

<h1>添加出版社</h1>

<form action="/add_publisher/" method="post">

    <input type="text" name="publisher_name">

    <input type="submit" value="提交">

</form>

</body>

</html>

在 app01/views.py 中添加 add_publisher 函数：

from django.shortcuts import render, redirect

from app01 import models

# Create your views here.

# 展示出版社列表

def publisher_list(request):

    # 去数据库查出所有的出版社，填充到 html 中，返回给用户

    ret = models.Publisher.objects.all().order_by("id")  # order_by("id") 通过 id 进行排序

    return render(request, "publisher_list.html", {"publisher_list": ret})

# 添加新的出版社

def add_publisher(request):

    # 如果是 POST 请求，就获取用户填写的数据

    if request.method == "POST":

        new_publisher = request.POST.get("publisher_name")

        # 获得数据后去数据库中新增一条数据

        models.Publisher.objects.create(name=new_publisher)

        # 添加成功后进行跳转

        return redirect("/publisher_list/")

    # 用户来到该界面返回的 html 页面

    return render(request, "add_publisher.html")

在 mysite0/urls.py 中添加对应关系

from django.conf.urls import url

from django.contrib import admin

from app01 import views

urlpatterns = [

    url(r'^admin/', admin.site.urls),

    url(r'^publisher_list/', views.publisher_list),

    url(r'^add_publisher/', views.add_publisher),

]

运行结果：

添加一个“丁出版社”

删除出版社：

修改 publisher_list.html，添加删除按钮

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>出版社列表</title>

</head>

<body>

<table border="1">

    <thead>

    <tr>

        <th>序号</th>

        <th>ID</th>

        <th>出版社名称</th>

        <th>操作</th>

    </tr>

    </thead>

    <tbody>

    {% for publisher in publisher_list %}

        <tr>

        <td>{{ forloop.counter }}</td>

        <td>{{ publisher.id }}</td>

        <td>{{ publisher.name }}</td>

        <td>

            <a href="/del_publisher/?id={{ publisher.id }}">删除</a>

        </td>

        </tr>

    {% endfor %}

    </tbody>

</table>

<a href="/add_publisher/">添加新的出版社</a>

</body>

</html>

app01/views.py 中添加 del_publisher 函数

from django.shortcuts import render, redirect, HttpResponse

from app01 import models

# Create your views here.

# 展示出版社列表

def publisher_list(request):

    # 去数据库查出所有的出版社，填充到 html 中，返回给用户

    ret = models.Publisher.objects.all().order_by("id")  # order_by("id") 通过 id 进行排序

    return render(request, "publisher_list.html", {"publisher_list": ret})

# 添加新的出版社

def add_publisher(request):

    # 如果是 POST 请求，就获取用户填写的数据

    if request.method == "POST":

        new_publisher = request.POST.get("publisher_name")

        # 获得数据后去数据库中新增一条数据

        models.Publisher.objects.create(name=new_publisher)

        # 添加成功后进行跳转

        return redirect("/publisher_list/")

    # 用户来到该界面返回的 html 页面

    return render(request, "add_publisher.html")

# 删除出版社

def del_publisher(request):

    # 从 GET 请求的参数中拿到要删除的 id 值

    del_id = request.GET.get('id', None)  # 取不到 id 值的话，默认为 None

    # 如果取到 id 值，就去数据库中删除该 id 的数据

    if del_id:

        # 根据 id 查找数据，并删除

        del_obj = models.Publisher.objects.get(id=del_id).delete()

        # 删除后返回页面

        return redirect("/publisher_list/")

    else:

        return HttpResponse("要删除的数据不存在！")

mysite0/urls.py 中添加对应关系

from django.conf.urls import url

from django.contrib import admin

from app01 import views

urlpatterns = [

    url(r'^admin/', admin.site.urls),

    url(r'^publisher_list/', views.publisher_list),

    url(r'^add_publisher/', views.add_publisher),

    url(r'^del_publisher/', views.del_publisher),

]

运行结果：

点击删除丁出版社

页面闪了一下，丁出版社就被删除了

编辑出版社：

修改 publisher_list.html

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>出版社列表</title>

</head>

<body>

<table border="1">

    <thead>

    <tr>

        <th>序号</th>

        <th>ID</th>

        <th>出版社名称</th>

        <th>操作</th>

    </tr>

    </thead>

    <tbody>

    {% for publisher in publisher_list %}

        <tr>

        <td>{{ forloop.counter }}</td>

        <td>{{ publisher.id }}</td>

        <td>{{ publisher.name }}</td>

        <td>

            <a href="/del_publisher/?id={{ publisher.id }}">删除</a>

            <a href="/edit_publisher/?id={{ publisher.id }}">编辑</a>

        </td>

        </tr>

    {% endfor %}

    </tbody>

</table>

<a href="/add_publisher/">添加新的出版社</a>

</body>

</html>

edit_publisher.html：

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>编辑出版社</title>

</head>

<body>

<h1>编辑出版社</h1>

<form action="/edit_publisher/" method="post">

    <input type="text" name="id" value="{{ publisher.id }}" style="display: none">

    <input type="text" name="publisher_name" value="{{ publisher.name }}">

    <input type="submit" value="提交">

</form>

</body>

</html>

在 app01/views.py 中添加 edit_publisher 函数

from django.shortcuts import render, redirect, HttpResponse

from app01 import models

# Create your views here.

# 展示出版社列表

def publisher_list(request):

    # 去数据库查出所有的出版社，填充到 html 中，返回给用户

    ret = models.Publisher.objects.all().order_by("id")  # order_by("id") 通过 id 进行排序

    return render(request, "publisher_list.html", {"publisher_list": ret})

# 添加新的出版社

def add_publisher(request):

    # 如果是 POST 请求，就获取用户填写的数据

    if request.method == "POST":

        new_publisher = request.POST.get("publisher_name")

        # 获得数据后去数据库中新增一条数据

        models.Publisher.objects.create(name=new_publisher)

        # 添加成功后进行跳转

        return redirect("/publisher_list/")

    # 用户来到该界面返回的 html 页面

    return render(request, "add_publisher.html")

# 删除出版社

def del_publisher(request):

    # 从 GET 请求的参数中拿到要删除的 id 值

    del_id = request.GET.get('id')

    # 如果取到 id 值，就去数据库中删除该 id 的数据

    if del_id:

        # 根据 id 查找数据，并删除

        del_obj = models.Publisher.objects.get(id=del_id).delete()

        # 删除后返回页面

        return redirect("/publisher_list/")

    else:

        return HttpResponse("要删除的数据不存在！")

# 编辑出版社

def edit_publisher(request):

    # 获取 POST 发来的数据，并更新到数据库中

    if request.method == "POST":

        # 获取 POST 传送来的 id 值和出版社

        edit_id = request.POST.get('id')

        new_name = request.POST.get('publisher_name')

        # 根据 id 取得出版社

        publisher = models.Publisher.objects.get(id=edit_id)

        publisher.name = new_name

        publisher.save()  # 把修改的结果提交到数据库

        return redirect("/publisher_list/")  # 跳转到列表页面

    # 从 GET 请求中取得 id 值

    publisher_id = request.GET.get('id')

    if publisher_id:

        # 获取当前编辑的出版社对象

        publisher_obj = models.Publisher.objects.get(id=publisher_id)

        return render(request, "edit_publisher.html", {"publisher": publisher_obj})

    else:

        return HttpResponse("编辑的出版社不存在！")

在 mysite0/urls.py 中添加对应关系

from django.conf.urls import url

from django.contrib import admin

from app01 import views

urlpatterns = [

    url(r'^admin/', admin.site.urls),

    url(r'^publisher_list/', views.publisher_list),

    url(r'^add_publisher/', views.add_publisher),

    url(r'^del_publisher/', views.del_publisher),

    url(r'^edit_publisher/', views.edit_publisher),

]

运行结果：