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1.默认外键序列化，使用外键的主键字段。

2.StringRelated外键序列化，使用外键表的 str方法进行序列化。

3.SlugRelated外键序列化，指定字段进行序列化。

4.PrimaryKeyRelatedField外键序列化，使用外键表的主键进行序列化。

5.外键自定义序列化方式，使用自定义方法进行序列化。

# 只能进行序列化，只能查询
class StudentSerializer2(serializers.ModelSerializer):
    # 1.使用外键表的 str方法进行序列化。
    # teacher = serializers.StringRelatedField()
    # 2.指定字段进行序列化。
    # teacher = serializers.SlugRelatedField(read_only=True, slug_field='tea_name')
    # 3.使用外键表的主键进行序列化。
    # teacher = serializers.PrimaryKeyRelatedField(read_only=True)
    # 4.使用自定义方法进行序列化,字段自定义(名字自己起)
    tea_name = serializers.SerializerMethodField(read_only=True)
    # 函数名以get_开头,再加上自定义字段名； obj就是模型类对象
    def get_tea_name(self, obj):
        return obj.teacher.tea_name
    class Meta:
        model = Student
        fields = '__all__'

问题:

要对子表学生表实现增删查改操作，并且要求展示外键的时候展示的是老师姓名，需要自己编写几个序列化器？

跟子表学生表相关的序列化器需要2个。

创建项目:django-admin startproject 项目名

创建子应用: python .manage.py startapp 应用名

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    
    'rest_framework',  # drf框架
    'corsheaders',  # 跨域
    'student',  # 子应用
]

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    # 'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
    
    'corsheaders.middleware.CorsMiddleware',  # 跨域中间件
]

CORS_ORIGIN_ALLOW_ALL = True  # 跨域 允许所有源访问

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'HOST': 'localhost',
        'PORT': 3306,
        'USER': 'root',
        'PASSWORD': 'root',
        'NAME': 'student',
    }
}

LANGUAGE_CODE = 'zh-Hans'

TIME_ZONE = 'Asia/Shanghai'

进入与项目同名的 init.py文件

import pymysql
pymysql.install_as_MySQLdb()

from django.db import models

# Create your models here.
class Teacher(models.Model):
    tea_name = models.CharField(max_length=20, verbose_name='老师姓名')

    class Meta:
        verbose_name = '老师表'
        verbose_name_plural = verbose_name
        db_table = 'teacher'

    def __str__(self):
        return self.tea_name

class Student(models.Model):
    stu_name = models.CharField(max_length=20, verbose_name='学生姓名')
    score = models.IntegerField(verbose_name='成绩')
    sex = models.CharField(max_length=5, verbose_name='性别')
    teacher = models.ForeignKey(to=Teacher, on_delete=models.CASCADE, verbose_name='老师')

    class Meta:
        verbose_name = '学生表'
        verbose_name_plural = verbose_name
        db_table = 'student'

    def __str__(self):
        return self.stu_name

生成迁移文件:python .manage.py makemigrations

执行迁移:python .manage.py migrate

创建超级用户:python .manage.py createsuperuser

注册模型类:

from django.contrib import admin
from student.models import Teacher, Student
# Register your models here.
admin.site.register(Teacher)
admin.site.register(Student)

运行项目并添加测试数据

在子应用下创建urls.py文件

# 子路由
from django.urls import path

urlpatterns = [
    
]

在与项目同名的文件夹下的 urls.py文件

# 主路由
from django.contrib import admin
from django.urls import path, include
from student import urls

urlpatterns = [
    path('admin/', admin.site.urls),
    path('', include(urls)),
]

在子应用下新建文件serializers.py文件，添加以下代码:

class TeacherSerializer(serializers.ModelSerializer):
    class Meta:
        model = Teacher
        fields = '__all__'

class StudentSerializer(serializers.ModelSerializer):
    class Meta:
        model = Student
        fields = '__all__'

from rest_framework.views import APIView
from rest_framework.response import Response
from student.models import Teacher, Student
from student.serializers import TeacherSerializer, StudentSerializer

# Create your views here.
class StudentsView(APIView):
    # 查询所有学生信息
    def get(self,request):
        students = Student.objects.all()  # 获取数据
        ser = StudentSerializer(instance=students, many=True)  # 序列化
        return Response(ser.data, status=200)

在子应用下创建urls.py文件

# 子路由
from django.urls import path

urlpatterns = [
    
]