python/Django（增、删、改、查）操作

python/Django（增、删、改、查）操作

我们要通过pycharm中的Django模块连接MySQL数据库进行对数据的操作。

一、创建Django项目（每创建一个项目都要进行以下设置）

1、如图所示，创建一个Project

2、红色区域是创建的项目名称，蓝色区域是创建目录

 3、如上图，把设置中这个注释掉

4、在设置文件中设置HTML文件夹路径

5、设置完文件夹路径，创建一个文件夹

二、连接数据库进行操作

建议：创建一个文件夹存放python代码，最后导入到urls.py文件中，如图：

在urls.py文件中设置url和相应的函数：

 urlpatterns = [
     # url(r'^admin/', admin.site.urls),
     url(r'^classes/', stter.classes),
     url(r'^add_class/', stter.add_class),
     url(r'^del_class/', stter.del_class),
     url(r'^update_class/', stter.update_class),
 ]

查看数据库class表的内容：

from django.shortcuts import render,redirect
##导入django模块下的返回方式和跳转模块
import pymysql
##导入pymysql模块
def classes(request):     ##定义查看数据库函数
    conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', password='', database='lian', charset='utf8')
    cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
    cursor.execute('select * from class')
    class_list = cursor.fetchall()
    cursor.close()
    conn.close()
    return render(request,'classes.html',{'class_list':class_list})
　　返回给用户（经过classes.html和用户浏览器渲染内容）{class_list}是传值到html中使用
------------------------------------------------------------------------
"D:\pycharm\PyCharm 2017.1\bin\runnerw.exe" D:\python3.6\python.exe E:/s4day65/manage.py runserver 8001
Performing system checks...

System check identified no issues (0 silenced).

You have 13 unapplied migration(s). Your project may not work properly until you apply the migrations for app(s): admin, auth, contenttypes, sessions.
Run 'python manage.py migrate' to apply them.
June 15, 2017 - 17:08:15
Django version 1.11.2, using settings 's4day65.settings'
Starting development server at http://127.0.0.1:8001/
Quit the server with CTRL-BREAK.
===============运行正常================

查看HTML代码：

 <!DOCTYPE html>
 <html lang="en">
 <head>
     <meta charset="UTF-8">
     <title>Title</title>
 </head>
 <body>
 <h1>班级列表</h1>
 <div>
     <a href="/add_class/">添加</a>
 </div>
 <table>
     <thead>
     <tr>
         <th>ID</th>
         <th>班级名称</th>
         <th>操作</th>
     </tr>
     </thead>

 {% for row in class_list%}     for 循环
     <tr>
         <td>{{ row.cid }}</td>
         <td>{{ row.cname }}</td>
         <td>
             <a href="/update_class/?nid={{ row.cid }}">编辑</a>
             |
             <a href="/del_class/?nid={{ row.cid }}">删除</a>
         </td>
     </tr>
 {% endfor %}      结束for循环  （开始结束一定要共存）
 </table>
 </body>
 </html>

运行效果：

添加：

 def add_class(request):   ##定义添加数据库函数
     if request.method == 'GET':
         return render(request,'add_class.html')
     else:
         print(request.POST)
         v=request.POST.get('cname')
         conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', password='', database='lian', charset='utf8')
         cursor = conn.cursor()
         cursor.execute("insert into class(cname) VALUES(%s)",[v,])
         conn.commit()
         cursor.close()
         conn.close()
         return redirect('/classes/')
 ---------------------------------------------------------------
 Performing system checks...

 System check identified no issues (0 silenced).

 You have 13 unapplied migration(s). Your project may not work properly until you apply the migrations for app(s): admin, auth, contenttypes, sessions.
 Run 'python manage.py migrate' to apply them.
 June 15, 2017 - 17:08:15
 Django version 1.11.2, using settings 's4day65.settings'
 Starting development server at http://127.0.0.1:8001/
 Quit the server with CTRL-BREAK.
 [15/Jun/2017 17:10:00] "GET /classes/ HTTP/1.1" 200 1396
 ===============================

添加的HTML代码：

 <!DOCTYPE html>
 <html lang="en">
 <head>
     <meta charset="UTF-8">
     <title>Title</title>
 </head>
 <body>
 <h1>添加班级</h1>
 <form method="POST" action="/add_class/">
     <p>班级名称：<input type="text" name="cname"></p>
     <input type="submit" value="提交">
 </form>
 </body>
 </html>

运行结果：

删除：

 def del_class(request):         ##定义删除数据库函数
     nid=request.GET.get('nid')
     conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', password='', database='lian', charset='utf8')
     cursor = conn.cursor()
     cursor.execute("delete from class WHERE cid=%s",[nid,])
     conn.commit()
     cursor.close()
     conn.close()
     return redirect('/classes/')

运行结果：

修改：

 def update_class(request):
     if request.method =='GET':
         nid = request.GET.get('nid')
         # name=request.POST.get('cname')
         conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', password='', database='lian', charset='utf8')
         cursor = conn.cursor()
         cursor.execute("select class.cid,class.cname from class where cid=%s", [nid,])
         ste = cursor.fetchone()
         return render(request, 'update_class.html', {'ste': ste})
     else:
         id=request.GET.get('nid')
         name=request.POST.get('cname')
         conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', password='', database='lian', charset='utf8')
         cursor = conn.cursor()
         cursor.execute("update class set cname=%s where cid = %s",[name,id,])
         conn.commit()
         cursor.close()
         conn.close()
         return redirect('/classes/')

修改HTML代码：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <h1>班级修改</h1>
    <form method="POST" action="/update_class/?nid={{ ste.0 }}">
        <p>班级名称：<input type="text" name="cname" value="{{ ste.1 }}"></p>
        <input type="submit" value="提交">
        {#    </form>#}
        {#    {% for row in ste %}#}
        {#    <a>{{ row }}</a>#}
        {#    {% endfor %}#}
    </form>
</body>
</html>

运行效果：