✍52 django向多张表添加数据

每个优秀的人都有一段沉默的时光，那段时光是付出了很多努力，却得不到结果的日子，我们把它叫做扎根。

原文链接 ： https://blog.csdn.net/Return_Li/article/details/106242343

同事遇到的多表数据写入和更新问题， 找到上面这篇文章， 记录下重点

示例 ：

• models.py

from django.db import models


# 品牌
class Brand(models.Model):
    name = models.CharField(max_length=20, verbose_name='名称')
    '''...其他字段省略....'''

    class Meta:
        db_table = 'tb_brand'

    def __str__(self):
        return self.name


# 分类
class Cate(models.Model):
    brand = models.ForeignKey(Brand, on_delete=models.CASCADE, related_name='brand_cate', null=True, blank=True, verbose_name='外键关联')
    cate_name = models.CharField(max_length=100, verbose_name='分类名称')
    '''...其他字段省略....'''

    class Meta:
        db_table = 'tb_cate'


# 商品
class Goods(models.Model):
    cate = models.ForeignKey ( Cate, on_delete=models.CASCADE, related_name='cate_goods', null=True, blank=True,
                                verbose_name='外键关联' )
    goods_name = models.CharField(max_length=50, verbose_name='商品名称')
    goods_size = models.CharField(max_length=50, verbose_name='商品规格')
    goods_count = models.CharField(max_length=100, verbose_name='商品数量')
    '''...其他字段省略....'''

    class Meta:
        db_table = 'tb_goods'

    def __str__(self):
        return self.goods_name

• views.py

from .serializers import *            
from rest_framework.views import APIView    
from rest_framework.response import Response  


class GoodsListView(APIView):
    def post( self, request):
        '''添加数据集'''
        data = request.data
        print(data)
        brand = BrandSerializer(data=data)
        if brand.is_valid():
            brand.save()
            return Response ( {'code': 200,"message":'SUCCESS'} )
        else:
            print(brand.errors)
            return Response ( {'code': 400, "message":'ERROR'} )

    def put( self, request):
        '''修改数据集'''
        data = request.data
        brand_instance = Brand.objects.get(id=data['id'])
        brand = BrandSerializer(brand_instance,data)
        if brand.is_valid():
            brand.save()
            return Response ( {'code': 200,"message":'SUCCESS'} )
        else:
            print(brand.errors)
            return Response ( {'code': 400, "message":'ERROR'} )

• serializer

from goods.models import *
from rest_framework import serializers

class GoodsSerializer(serializers.ModelSerializer):

    class Meta:
        model = Goods
        fields = ('id', 'goods_name', 'goods_count', 'goods_size')


class CateSerializer(serializers.ModelSerializer):

    cate_goods = GoodsSerializer ( many=True )

    class Meta:
        model = Cate
        fields = ('id', 'cate_name', 'cate_goods')


class BrandSerializer(serializers.ModelSerializer):

    brand_cate = CateSerializer ( many=True )

    class Meta:
        model = Brand
        fields = ('id', 'name', 'brand_cate')

    def create(self, validated_data):
        # pop 弹出 data 中的数据并保存
        brand_cates = validated_data.pop('brand_cate')
        # 并进行第一张表的添加
        brand = Brand.objects.create(**validated_data)
        # 遍历 弹出的第二张表的数据并添加第二章表, 且主键信息为单独添加
        for cate_data in brand_cates:
            cate_goods = cate_data.pop ( 'cate_goods' )
            cate = Cate.objects.create(brand=brand, **cate_data)
            # 第三张表数据添加
            for goods in cate_goods:
                Goods.objects.create (cate=cate, **goods)
        return brand

    def update(self, instance, validated_data):
        # 获取当前json 数据中 外键表的数据
        brand_cate = validated_data.pop('brand_cate')
        # 通过 instance 实例 去获取它外键表的实例
        brand_cate_data = (instance.brand_cate).all()
        brand_cate_data = list(brand_cate_data)
        # 修改 当前实例表的数据
        instance.name = validated_data.get('name', instance.name)
        instance.save()
        # 遍历 pop弹出的 外键表要修改的数据
        for cate_data in brand_cate:
            # 继续弹出第三张表外键的数据
            goods_data = cate_data.pop ( 'cate_goods' )
            # 获取第一张外键的 实例
            cate_instance = brand_cate_data.pop(0)
            # 获取第三张表的实例
            cate_goods = list((cate_instance.cate_goods).all())
            # 更新 第一张外键表数据
            cate_instance.name = cate_data.get('cate_name', cate_instance.cate_name)
            cate_instance.save()
            # 遍历继续更新第三张表的数据
            for goods in goods_data:
                goods_instance = cate_goods.pop(0)
                goods_instance.goods_name = goods.get("goods_name",goods_instance.goods_name)
                goods_instance.goods_count = goods.get("goods_count",goods_instance.goods_count)
                goods_instance.goods_size = goods.get("goods_size",goods_instance.goods_size)
                goods_instance.save()
        return instance