关于Django框架的关系模型序列化和一对多关系中的序列化解析

from django.db import models
# Create your models here.
class Classes(models.Model):
    name = models.CharField(max_length=20, verbose_name='班级名称')
class Student(models.Model):
    SEX_CHOICES = ((1,'男'),(2,'女'))
    name = models.CharField(max_length=20,verbose_name='姓名')
    age = models.IntegerField(null=True, blank=True, verbose_name='年龄')
    sex = models.IntegerField(choices=SEX_CHOICES,default=1,verbose_name='性别')
    # 多方建立外键
    classes = models.ForeignKey(Classes, on_delete=models.SET_NULL, null=True, verbose_name='班级')

from rest_framework import serializers
from rest_app.models import *
class ClassesSerializer(serializers.ModelSerializer):
    class Meta:
        model = Classes
        fields = ['id', 'name']
class StudentSerializer(serializers.ModelSerializer):
    # 新增班级属性
    classes = ClassesSerializer() # 一定要加括号，创建实例对象。否则，只能输出id
    class Meta:
        model = Student
        fields = ['id', 'name', 'age', 'sex','classes'] #或者 ='__all__'

from django.shortcuts import render
from django.views.decorators.csrf import csrf_exempt
from rest_app.models import *
from rest_app.app_serializer import StudentSerializer,ClassesSerializer
from django.http import JsonResponse,HttpResponse
from rest_framework.parsers import JSONParser
###################一对多关系表的增删改查####################
# 完成新增 查询所有，路由相同，但是请求方式不同
@csrf_exempt # 关闭csrf中间件（防止利用cookie和token攻击网站）的使用
def classes(request):
    # 判断请求方式，完成新增和查询所有
    if request.method == 'GET':
        # 查询所有数据
        stu_list = Classes.objects.all() 
        # 序列化
        serializer = ClassesSerializer(stu_list, many=True)
        # 将json格式返回客户端
        return JsonResponse(serializer.data, safe=False)
    elif request.method == 'POST':
        # 新增数据
        # 使用JSONParaser调用parse()进行反序列化为字典
        data_dict = JSONParser().parse(request)
        # 将字典传入到序列化类中
        serializer = ClassesSerializer(data=data_dict)
        # 进行验证
        if serializer.is_valid():
            # 保存数据到数据库中
            serializer.save()
            # 返回新保存的数据  状态码 201
            return JsonResponse(serializer.data, status = 201)
        return JsonResponse(serializer.errors, status=400)
# 查询一个 删除   修改
@csrf_exempt # 关闭csrf中间件（防止利用cookie和token攻击网站）的使用
def classes_detail(request,pk):
    try:
        # 根据pk获取Classes
        classes = Classes.objects.get(pk=pk)
    except Classes.DoesNotExist: #无法获取到
        return HttpResponse(status=404)
    if request.method == 'GET':
        # 根据id查询指定的Student
        # 序列化——展示数据
        serializer = ClassesSerializer(classes)
        # 返回json数据
        return JsonResponse(serializer.data)
    elif request.method == 'PUT':
        # 根据id修改Student
        # 反序列化——获取需要使用的数据时使用
        data_dict = JSONParser().parse(request)
        # 将原来的对象 字典数据传入序列化类中
        serializer = ClassesSerializer(classes, data=data_dict)
        # 进行验证
        if serializer.is_valid():
            # 更新数据到数据库
            serializer.save()
            return JsonResponse(serializer.data)
        return JsonResponse(serializer.errors, status=400)
    elif request.method == 'DELETE':
        # 根据id删除classes
        classes.delete()
        return HttpResponse(status=200)

from django.db import models
# Create your models here.
class Classes(models.Model):
    name = models.CharField(max_length=20, verbose_name='班级名称')
class Student(models.Model):
    SEX_CHOICES = ((1,'男'),(2,'女'))
    name = models.CharField(max_length=20,verbose_name='姓名')
    age = models.IntegerField(null=True, blank=True, verbose_name='年龄')
    sex = models.IntegerField(choices=SEX_CHOICES,default=1,verbose_name='性别')
    # 多方建立外键
    classes = models.ForeignKey(Classes, related_name='students' ,on_delete=models.SET_NULL, null=True, verbose_name='班级')

from rest_framework import serializers
from rest_app.models import *
# 根据学生获取学生所在班级
# class ClassesSerializer(serializers.ModelSerializer):
#     class Meta:
#         model = Classes
#         fields = ['id', 'name']
# class StudentSerializer(serializers.ModelSerializer):
#     # 新增班级属性
#     classes = ClassesSerializer() # 一定要加括号，创建实例对象。否则，只能输出id
#     class Meta:
#         model = Student
#         fields = ['id', 'name', 'age', 'sex','classes'] #或者 ='__all__'
# 根据班级获取班级所有学生信息
class StudentSerializer(serializers.ModelSerializer):
    class Meta:
        model = Student
        fields = ['id', 'name', 'age', 'sex'] #或者 ='__all__'
class ClassesSerializer(serializers.ModelSerializer):
    # students 属性要和student类中外键classes属性 related_name='students'
    # 多条记录 指定many = True, read_only=True
    students = StudentSerializer(many=True, read_only=True) 
    class Meta:
        model = Classes
        fields = ['id', 'name','students']        

from rest_framework import serializers
from rest_app.models import *
# 根据学生获取学生所在班级
# class ClassesSerializer(serializers.ModelSerializer):
#     class Meta:
#         model = Classes
#         fields = ['id', 'name']
# class StudentSerializer(serializers.ModelSerializer):
#     # 新增班级属性
#     classes = ClassesSerializer() # 一定要加括号，创建实例对象。否则，只能输出id
#     class Meta:
#         model = Student
#         fields = ['id', 'name', 'age', 'sex','classes'] #或者 ='__all__'
class ClassesRelatedField(serializers.RelatedField):
    def to_representation(self, value):
        return {'id':value.id, 'name':value.name}
# 根据班级获取班级所有学生信息
class StudentSerializer(serializers.ModelSerializer):
    # classes 属性名和Student类中外键属性名相同
    classes = ClassesRelatedField(read_only=True)
    class Meta:
        model = Student
        fields = ['id', 'name', 'age', 'sex','classes'] #或者 ='__all__'
class ClassesSerializer(serializers.ModelSerializer):
    # students 属性要和student类中外键classes属性 related_name='students'
    # 多条记录 指定many = True, read_only=True
    students = StudentSerializer(many=True, read_only=True) 
    class Meta:
        model = Classes
        fields = ['id', 'name','students']