django单表操作，增、删、改、查

一、实现：增、删、改、查

1、获取所有数据显示在页面上

model.Classes.object.all()，拿到数据后，渲染给前端;前端通过for循环的方式，取出数据。

目的：通过classes（班级表数据库）里面的字段拿到对应的数据。

2、添加功能

配置url分发路由增加一个add_classes.html页面

写一个def add_classess函数

在前端写一个a标签，前端页面就可以看到一个添加链接，通过点这个a标签的链接跳转到一个新的add_classess页面

add_classess.html 页面中实现两个功能：

form表单 ：返回给add_classess.html页面

input  输入框

input  提交按钮

接下来就要接收前端输入的数据：

if  request.mothod='GET'

elif

request.mothod='POST'

request.POST.get('title')  拿到传过来的班级数据

然后通过创建的方式，写入对应的title字段数据库中

方法：models.Classes.objects.create(titile=title)

再返回给return redirect('/get_classes.html')

3、删除功能

配置url路由分发

加一个操作：

<th>操作</th>

一个a标签：

<a href="/del_classes.html?nid={{ row.id }}">删除</a>

实现删除操作，就是找到数据库中，对应的id字段(赋值给nid=id)，删除掉这个ID字段这行数据，就实现了删除功能。

4、实现编辑功能

在get_classes.html里添加一个a标签

配置路由分发

写def edit_classes函数

班级这个输入框前面id不显示,因为id不能被用户修改，所以要隐藏。

根据id拿到这个对象（id 走get方法），id存放在请求头中发送过去的。

obj对象里面包含id 和 title ，走post方法，title是放在请求体中发送过去的

第一次：get拿到id

    if request.method == 'GET':
        nid = request.GET.get('nid')
        obj = models.Classes.objects.filter(id=nid).first()
        return render(request, 'edit_classes.html', {'obj': obj})

第二次：post拿到id和title

    elif request.method == 'POST':
        nid = request.GET.get('nid')
        title = request.POST.get('title')
        models.Classes.objects.filter(id=nid).update(titile=title)
        return redirect('/get_classes.html')

综合应用示例：

models.py

from django.db import models

# Create your models here.

class Classes(models.Model):
    """
    班级表,男
    """
    titile = models.CharField(max_length=32)
    m = models.ManyToManyField("Teachers")

class Teachers(models.Model):
    """
    老师表，女
    """
    name = models.CharField (max_length=32)

"""
cid_id  tid_id
   1
   2
   1
 1000
"""
# class C2T(models.Model):
#     cid = models.ForeignKey(Classes)
#     tid = models.ForeignKey(Teachers)

class Student(models.Model):
    username = models.CharField(max_length=32)
    age = models.IntegerField()
    gender = models.BooleanField()
    cs = models.ForeignKey(Classes)

urls.py

"""django_one URL Configuration

The `urlpatterns` list routes URLs to views. For more information please see:
    https://docs.djangoproject.com/en/1.10/topics/http/urls/
Examples:
Function views
    1. Add an import:  from my_app import views
    2. Add a URL to urlpatterns:  url(r'^$', views.home, name='home')
Class-based views
    1. Add an import:  from other_app.views import Home
    2. Add a URL to urlpatterns:  url(r'^$', Home.as_view(), name='home')
Including another URLconf
    1. Import the include() function: from django.conf.urls import url, include
    2. Add a URL to urlpatterns:  url(r'^blog/', include('blog.urls'))
"""
from django.conf.urls import url
from django.contrib import admin
from app01.views import classes

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^get_classes.html$', classes.get_classes),
    url(r'^add_classes.html$', classes.add_classes),
    url(r'^del_classes.html$', classes.del_classes),
    url(r'^edit_classes.html$', classes.edit_classes),

]

classes.py

from django.shortcuts import render
from django.shortcuts import redirect
from app01 import models

def get_classes(request):
    cls_list = models.Classes.objects.all()
    return render(request, 'get_classes.html', {'cls_list': cls_list})

def add_classes(request):
    if request.method == "GET":
        return render(request, 'add_classes.html')
    elif request.method == 'POST':
        title = request.POST.get('titile')
        models.Classes.objects.create(titile=title)
        return redirect('/get_classes.html')

def del_classes(request):
    nid = request.GET.get('nid')
    models.Classes.objects.filter(id=nid).delete()
    return redirect('/get_classes.html')

def edit_classes(request):
    if request.method == 'GET':
        nid = request.GET.get('nid')
        obj = models.Classes.objects.filter(id=nid).first()
        return render(request, 'edit_classes.html', {'obj': obj})
    elif request.method == 'POST':
        nid = request.GET.get('nid')
        title = request.POST.get('title')
        models.Classes.objects.filter(id=nid).update(titile=title)
        return redirect('/get_classes.html')

get_classes.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div>
    <a href="/add_classes.html">添加</a>
</div>
<div>
    <table border="">
        <thead>
        <tr>
            <th>ID</th>
            <th>名称</th>
            <th>操作</th>
        </tr>
        </thead>
        <tbody>
        {% for row in cls_list %}
            <tr>
                <td>{{ row.id }}</td>
                <td>{{ row.titile }}</td>
                <td>
                    <a href="/del_classes.html?nid={{ row.id }}">删除</a>
                    |
                    <a href="/edit_classes.html?nid={{ row.id }}">编辑</a>
                </td>
            </tr>
        {% endfor %}
        </tbody>
    </table>
</div>
</body>
</html>

add_classes.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="add_classes.html" method="POST">
    {% csrf_token %}
    <input type="text" name="titile" />
    <input type="submit" value="提交" />
</form>
</body>
</html>

edit_classes.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
    <form action="/edit_classes.html?nid={{ obj.id }}" method="POST">
        {% csrf_token %}
    <input type="text" name="title" value="{{ obj.titile }}" />
    <input type="submit" value="提交"/>
</form>
</body>
</html>