Django ORM 实现数据的单表增删改查

一、配置环境

1 Django 连接数据库(MySQL)

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'xyz',
        'USER':'root',
        'PASSWORD':'root',
        'HOST':'IP地址',
        'PORT':3306,
        'CHARSET':'utf8'
    }
}

2 Django 默认用的是 mysqldb 改为用 pymysql 连接

import pymysql
pymysql.install_as_MySQLdb()

3 安装 pymysql

pip3 install pymysql

4 定义 models

from django.db import models

# Create your models here.

class User(models.Model):
    # id int primary_key auto_increment
    id = models.AutoField(primary_key=True, verbose_name='主键')
    # username varchar(32)
    username = models.CharField(max_length=32, verbose_name='用户名')
    password = models.CharField(max_length=64, verbose_name='密码')

5 执行迁移，同步。顺序执行下面个代码（每次修改表都要顺序执行一遍）

python manage.py makemigrations
python manage.py migrate

6 定义 url

from django.contrib import admin
from django.urls import path
from app import views

urlpatterns = [
    path('admin/', admin.site.urls),
    # 注册功能
    path('register/',views.reg),
    # 展示用户列表
    path('userlist/',views.userlist),
    # 编辑用户
    path('edit_user/',views.edit_user),
    # 删除用户
    path('delete_user/',views.delete_user)
]

二、增加

新建 templates\register.html 文件

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link href="https://cdn.bootcss.com/twitter-bootstrap/3.4.1/css/bootstrap.min.css" rel="stylesheet">
    <script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.min.js"></script>
    <script src="https://cdn.bootcss.com/twitter-bootstrap/3.4.1/js/bootstrap.min.js"></script>
</head>
<body>
<h1 class="text-center">注册</h1>
<div class="container">
    <div class="row">
        <div class="col-md-8 col-md-offset-2">
            <form action="" method="post">
                <p>username:<input type="text"     name="username" class="form-control"></p>
                <p>password:<input type="password" name="password" class="form-control"></p>
                <input type="submit" class="btn btn-danger btn-block">
            </form>
        </div>
    </div>
</div>
</body>
</html>

获取用户数据，并存入数据库

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

def register(request):
    if request.method == "POST":
        username = request.POST.get('username')
        password = request.POST.get('password')
       
        # 第一种增加
        # res = models.User.objects.create(username=username, password=password)
        # 返回值就是当前被创建的对象本身
        # print(res,res.username, res.password)

        # 第二种增加
        user_obj = models.User(username = username, password = password)
        # 保存数据
        user_obj.save()  
        
    # 先给用户返回一个注册页面
    return render(request, 'register.html')

三、查询

def userlist(request):
    # 查询出用户表里面所有的数据
    # 方式1
    # filter括号内可以携带多个参数 参数与参数之间默认是and关系。可以把filter 想成where
    # data = models.User.objects.filter()
    # print(data)

    # 方式2
    user = models.User.objects.all()
    # return render(request,'userlist.html', {'user_queryset':user_queryset})

    return render(request, 'userlist.html', locals())

新建 templates\userlist.html 文件

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link href="https://cdn.bootcss.com/twitter-bootstrap/3.4.1/css/bootstrap.min.css" rel="stylesheet">
    <script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.min.js"></script>
    <script src="https://cdn.bootcss.com/twitter-bootstrap/3.4.1/js/bootstrap.min.js"></script>
</head>
<body>
<h1 class="text-center">数据展示</h1>
<div class="container">
    <div class="row">
        <div class="col-md-8 col-md-offset-2">
            <table class="table table-striped table-hover">
                <thead>
                    <tr>
                        <th>ID</th>
                        <th>username</th>
                        <th>password</th>
                        <th>action</th>
                    </tr>
                </thead>
                <tbody>
                    {% for user_obj in user %}
                        <tr>
                            <td>{{ user_obj.id }}</td>
                            <td>{{ user_obj.username }}</td>
                            <td>{{ user_obj.password }}</td>
                            <td>
                                <a href="/edit_user/?user_id={{ user_obj.id }}"   class="btn btn-primary btn-xs">编辑</a>
                                <a href="/delete_user/?user_id={{ user_obj.id }}" class="btn btn-danger btn-xs">删除</a>
                            </td>
                        </tr>
                    {% endfor %}
                </tbody>
            </table>
        </div>
    </div>
</div>
</body>
</html>

四、修改

def edit_user(request):
    # 获取url问号后面的参数
    edit_id = request.GET.get('user_id')
    # 查询当前用户想要编辑的数据对象
    edit_obj = models.User.objects.filter(id = edit_id).first()

    if request.method == "POST":
        username = request.POST.get('username')
        password = request.POST.get('password')
        # 去数据库中修改对应的数据内容
        # 修改数据方式1
        # models.User.objects.filter(id=edit_id).update(username=username,password=password)
        """
            将filter查询出来的列表中所有的对象全部更新            批量更新操作
            只修改被修改的字段
        """

        # 修改数据方式2
        edit_obj.username = username
        edit_obj.password = password
        edit_obj.save()
        """
            上述方法当字段特别多的时候效率会非常的低
            从头到尾将数据的所有字段全部更新一边 无论该字段是否被修改
        """

        # 跳转到数据的展示页面
        return redirect('/userlist/')

    # 将数据对象展示到页面上
    return render(request, 'edit_user.html', locals())

新建 templates\edit_user.html 文件

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link href="https://cdn.bootcss.com/twitter-bootstrap/3.4.1/css/bootstrap.min.css" rel="stylesheet">
    <script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.min.js"></script>
    <script src="https://cdn.bootcss.com/twitter-bootstrap/3.4.1/js/bootstrap.min.js"></script>
</head>
<body>

<h1 class="text-center">编辑</h1>
<div class="container">
    <div class="row">
        <div class="col-md-8 col-md-offset-2">
            <form action="" method="post">
                <p>username:<input type="text" name="username" class="form-control" value="{{ edit_obj.username }}"></p>
                <p>password:<input type="text" name="password" class="form-control" value="{{ edit_obj.password }}"></p>
                <input type="submit" class="btn btn-info btn-block" value="编辑">
            </form>
        </div>
    </div>
</div>
</body>
</html>

五、删除

def delete_user(request):
    # 获取用户要删除的数据 id值
    delete_id = request.GET.get('user_id')
    # 直接去数据库中找到对应的数据删除即可
    models.User.objects.filter(id = delete_id).delete()
    # 跳转到展示页面
    return redirect('/userlist/')

Django ORM 实现数据的单表 增删改查