django ManyToMany添加数据、展示数据

1.在modle.py中创建多对多数据库

from django.db import models

class Role(models.Model):
      role_name = models.CharField(max_lenth=12,verbose_name='角色',null=True)

class User(models.Model):
      name = models.CharField(max_lenth=32,verbose_name='用户',null=True)
      roles = models.ManyToManyField(Role)

2.在创建一个serialzer.py用来写序列化

from rest_framework import serializer
from .models import * 

class RoleSer(serializers.ModelSerializer)
       class Meta:
            model = Role     # 指定数据库
            fields = '__all__   

class UserSer(serializers.ModelSerializer):
      class Meta:
            model = User            # 指定数据库
            fields = '__all__'           # 指定字段 all为所有字段

3.在views.py中开始写逻辑

from django.shortcuts import render
from rest_framework.views import APIView
from rest_framework.response import Response
from user.models import *
# from user.serializers import *
from .serializer import *
# Create your views here.

class UserManyToMany(ApiView):
       # 展示数据
      def get(serlf,request):
            # 获取数据
             u_id = request.query_params.get('u_id')      # 获取u_id
             r_id = request.query_params.get('r_id')      # 获取r_id

            # 验证数据
            if not all([u_id,r_id]):      # 判断数据是否为空
                  return Response({'code':4001,'msg':'参数不全'})

            # 逻辑与入库
            # 知道ManyToMany字段是的查询方式
            user_obj = User.object.get(id=u_id)
            role_obj = user_obj.roles.all()
            ser_obj = RoelSer(role_obj,many=True)

            # 在不知道使用ManyToMany字段的查询方式
            role_obj = Role.object.get(id=r_id)
            user_obj = role_obj.user_set.all()
            ser_obj = UserSer(user_obj,many=True)
                 
            # 返回数据
            return Response({'code':200,'data':ser_obj.data})

      # 添加数据
      def post(self,request):
            # 获取数据
            r_name = request.data.get('r_name')      # 获取role_name
            u_name = request.data.get('u_name')      # 获取name
            
            # 验证数据
            if not all([r_name,u_name]):      # 判断参数是否存在
                  return Response({'code':4001,'msg':'参数不全})
            
            # 逻辑与入库
            # 反向添加
            # user_obj = User.object.get(name=u_name)
            # role_obj = Role.object.get(role_name=r_name)
            # user_obj.roles.add(role_obj)
            
            # 反向添加
            user_obj = User.object.filter(name=u_name)
            role_obj = Role.object.get(role_name=r_name)
            role_obj.user_set.add(*user_obj)      # *号代表多条数据

            return Response('code':200,'msg':'成功')