数据的增删改查(insert update delete select)
# 用户列表的展示：
# 把数据表中得用户数据都给查询出来展示在页面上
1. 查询
from app01 import models models.UserInfo.objects.all() # 查询所有的字段信息和数据 res=models.UserInfo.objects.first() # 查询一条，而且是第一条，queryset对象，列表套对象的形式 if res: res[0] try: res[0] # 它是支持索引取值的，如果是第一条就直接first() select * from userinfo where username ='' and password = ''; res=models.UserInfo.objects.filter(username='', password='').first() # and res=models.UserInfo.objects.filter(username='').filter(password='').filter().first() # and """链式表达式的思想，jQuery中也有这样的写法""" models.UserInfo.objects.all()[0] models.UserInfo.objects.all()[0:2] # 支持切片2. 增加
models.UserInfo.objects.create(username='', password='') res=models.UserInfo(username='', password='') res.save() # 真正的操作数据库3、修改数据的逻辑分析
# 1. 先确定修改哪条记录------>怎么样确定修改哪条记录?
# 2. 通过什么字段可以确定唯一一条记录? 主键id，要携带主键id到后端.
# 3. 在后端接收主键id值，然后根据这个id值再去表中查询数据，查询一条
# 4. 然后把查询的数据在渲染到页面中，然后在修改models.UserInfo.objects.filter(pk=1).update(username='', password='') res=models.UserInfo.objects.first() res.username=''; res.password='' res.save() # 真正的操作数据库4、删除功能的分析
# 1. 给删除按钮加一个链接，携带当前记录的id值
# 2. 后端要接收这个主键id值
# 3. 后端直接执行删除操作models.UserInfo.objects.filter(pk=1).delete() res.delete()
数据的增删改查汇总
"views.py"
from django.shortcuts import render,HttpResponse,reverse,redirect # Create your views here. def home(request): print('request') return HttpResponse('/home/') from app01 import models def login(request): print(request.method,type(request.method)) if request.method == 'POST': username = request.POST.get('username') password = request.POST.get('password') print(request.POST.getList('hobby')) res = models.UserInfo.objects.filter(username='123',password='123').all() print(res) res.username='' res.password='' if username == 'kevin' and password == '123': print('登录成功') models.UserInfo.objects.create(username='kevin',password='123') return redirect('/index/') else: return HttpResponse("用户名或密码错误") print(request.GET) print(request.GET.get('a')) print(request.GET.get('b')) print(request.GET.get('c')) print(request.GET.get('c')) print(request.GET.getlist('c')) return render(request,'login.html') def userlist(request): user_list=models.UserInfo.objects.all()#查询所有信息 """这里不之处负数切片""" # user_list=models.UserInfo.objects.all()[0:2] # 查询所有的数据 '''支持for循环''' # for i in user_list: # print(i.gender) ## queryset对象就是一个列表套对象的形式 # <QuerySet [<UserInfo: UserInfo object>, <UserInfo: UserInfo object>, <UserInfo: UserInfo object>]> # print(user_list[0]) print(user_list[0].username) return render(request,'userlist.html',locals()) def edit(request): edit_id = request.GET.get('id') edit_ibj = models.UserInfo.objects.filter(id=edit_id).first() if request.method == 'POST': hidden_id = request.POST.get('hidden_id') username = request.POST.get('username') password = request.POST.get('password') gender = request.POST.get('gender') # 修改 affect_rows = models.UserInfo.objects.filter(pk=hidden_id).update(username=username,password=password,gender=gender) return redirect('/userlist/') return render(request,'edit.html',locals()) def delete(request): delete_id = request('/userlist/') return redirect('/userlist/') def add(request): if request.method == 'POST': username = request.POST.get('username') password = request.POST.get('password') gender = request.POST.get('gender') user_obj = models.UserInfo(username=username,password=password,gender=gender) user_obj.save() return redirect('/userlist/') return render(request,'add.html') def ab_render(request): user_dict1 = {'username':'kevin','password':123} user_dict1 = {'a':1} print(locals()) return render(request,'')"urls.py"
from django.contrib import admin from django.urls import path from app01 import views urlpatterns = [ path('admin/', admin.site.urls), path('login/', views.login), path('home/', views.home), path('userlist/', views.userlist), path('edit/', views.edit), path('delete/', views.delete), path('add/', views.add), path('ab_render/', views.ab_render), ]"models.py"
from django.db import models # Create your models here. class UserInfo(models.Model): username = models.CharField(max_length=32,verbose_name='用户名') password = models.CharField(max_length=64,verbose_name='密码') gender = models.CharField(max_length=32) def __str__(self): return self.username"__init__.py"
import pymysql pymysql.install_as_MySQLdb()前端："ab_render.html"
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.7.1/jquery.min.js"></script> <link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"> <script src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script> </head> <body> {{ user_dict.username }} {{ user_dict.password }} {{ user_dict1 }} {{ user_dict1.a }} </body> </html>"add.html"
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.7.1/jquery.min.js"></script> <link rel="stylesheet" href="bootstrap-3.4.1-dist/css/bootstrap.min.css"> <script src="bootstrap-3.4.1-dist/js/bootstrap.min.js"></script> </head> <body> <div class="container"> <div class="row"> <h1 class="text-center">添加页面</h1> <form action="" method="post"> <div class="form-group"> 用户名：<input type="text" class="form-control" name="username"> </div> <div class="form-group"> 密码：<input type="password" class="form-control" name="password"> </div> <div class="form-group"> 性别：<input type="text" class="form-control" name="gender"> </div> </form> </div> </div> </body> </html>"edit.html"
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.7.1/jquery.min.js"></script> <link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"> <script src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script> </head> <body> <div class="container"> <div class="row"> <h1 class="text-center">修改页面</h1> <form action="" method="post"> <input type="hidden" value="{{ edit_obj.pk }}" name="hidden_id"> <div class="form-group"> 用户名： <input type="text" class="form-control" name="username" value="{{ edit_obj.username }}"> </div> <div class="form-group"> 密码： <input type="password" class="form-control" name="password" value="{{ edit_obj.password }}"> </div> <div class="form-group"> 性别： <input type="text" class="form-control" name="gender" value="{{ edit_obj.gender }}"> </div> <div class="form-group"> <input type="submit" class="btn btn-info btn-block" value="提交"> </div> </form> </div> </div> </body> </html>"index.html"
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.7.1/jquery.min.js"></script> <link rel="stylesheet" href="bootstrap-3.4.1-dist/css/bootstrap.min.css"> <style> h1{ color: hotpink; } </style> </head> <body> <h1>第一个模板文件</h1> </body> </html>"login.html"
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.7.1/jquery.min.js"></script> <link rel="stylesheet" href="bootstrap-3.4.1-dist/css/bootstrap.min.css"> <script src="bootstrap-3.4.1-dist/js/bootstrap.min.js"></script> </head> <body> <div class="container"> <div class="row"> <h1 class="text-center">登录页面</h1> <form action="" method="post"> <div class="form-group"> 用户名：<input type="text" class="form-control " name="username"> </div> <div class="form-group"> 密码：<input type="password" class="form-control " name="password"> </div> <div class="form-group"> <input type="checkbox" name="hobby" value="a"> <input type="checkbox" name="hobby" value="b"> <input type="checkbox" name="hobby" value="c"> </div> <div class="form-group"> <input type="submit" class="btn btn-success btn-block" value="登录"> </div> </form> </div> </div> </body> </html>"userlist.html"
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.7.1/jquery.min.js"></script> <link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"> <script src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script> </head> <body> <div class="container"> <div class="row"> <h1 class="text-center">用户列表</h1> <a href="/add/" class="btn btn-success">添加用户</a> <table class="table table-striped table-hover table-bordered"> <thead> <tr> <th>ID</th> <th>username</th> <th>password</th> <th>gender</th> <th>action</th> </tr> </thead> <tbody> {% for user in user_list %} <tr> <td>{{ user.id }}</td> <td>{{ user.username }}</td> <td>{{ user.password }}</td> <td>{{ user.gender }}</td> <td> <a href="/edit/?id={{ user.id }}" class="btn btn-success">修改</a> <a href="/del/?id={{ user.pk }}" class="btn btn-danger">删除</a> </td> </tr> {% endfor %} </tbody> </table> </div> </div> </body> </html>
如何创建表关系(一对一 一对多 多对多)
### 换位思考法判断表关系
图书表和出版社表 >>> 一对多 >>> 图书表是多，出版社是一 >>> 建在多的一方
图书表和作者表 >>> 多对多 >>> 需要第三张表
作者表和作者详情表 >>> 一对一 >>> 外键字段一般建在查询频率较高的### 在Django中如何创建表关系
"""回头复习表关系"""class Book(models.Model): title = models.CharField(max_length=64) """ max_digits=None,:总位数 decimal_places=None：小数位数 """ # price decimal(8,2) price = models.DecimalField(max_digits=8, decimal_places=2) # publish_id = models.ForeignKey(to='Publish', to_field='id') """对于外键字段关系，会自动帮我们拼接_id""" publish = models.ForeignKey(to='Publish') """authors它是一个虚拟字段，它不会实际在表中创建出来这个字段，这一句可以自动帮助我们创建出来第三张表""" authors = models.ManyToManyField(to='Author')"""出版社表"""
class Publish(models.Model): name = models.CharField(max_length=64) addr = models.CharField(max_length=64)"""作者表"""
class Author(models.Model): name = models.CharField(max_length=64) author_detail = models.OneToOneField(to='AuthorDetail')"""作者详情表"""
class AuthorDetail(models.Model): phone = models.CharField(max_length=64) email = models.CharField(max_length=64)
Django的请求生命周期流程图
"""它可以帮助你们熟练django的一个完整执行流程"""
