黑马程序员技术交流社区

标题: 【武汉校区】Django模型关系建表查询和序列化嵌套使用 [打印本页]

作者: 武汉分校-小舞 时间: 2018-12-18 14:26
标题: 【武汉校区】Django模型关系建表查询和序列化嵌套使用
本帖最后由武汉分校-小舞于 2018-12-18 14:34 编辑

Django模型关系建表查询和序列化嵌套使用

模型部分

1.一对一

模型：

class Class(models.Model):
id = models.AutoField(primary_key=True)
cname = models.CharField(max_length=32)
cdata = models.DateField()

def __str__(self):
      return self.cname

class Student(models.Model):
id = models.AutoField(primary_key=True)
sname = models.CharField(max_length=32)
# 一对多
# cid = models.ForeignKey(to="Class",to_field="id",related_name="student")
cid = models.ForeignKey(Class, to_field="id",related_name='class_related')
# 一对一
detail = models.OneToOneField(StudentDetail, to_field="id",related_name='detail_related')
# 等同于如下的代码
# detail = models.ForeignKey(to="StudentDetail",to_field="id",unique=True)

class StudentDetail(models.Model):
id = models.AutoField(primary_key=True)
height = models.PositiveIntegerField()
email = models.EmailField()
memo = models.CharField(max_length=128)
查询：

#正向查询（由学生信息表查询学生详情表）
stu = models.Student.objects.first()
stu.detail.email
'234@qq'
#反向查询（由学生详情表反向查询学生信息表）
std = StudentDetail.objects.first()
std.detailtostudent_related
'小明'
2.一对多

模型：

class Class(models.Model):
id = models.AutoField(primary_key=True)
cname = models.CharField(max_length=32)
cdata = models.DateField()

def __str__(self):
      return self.cname

class Student(models.Model):
id = models.AutoField(primary_key=True)
sname = models.CharField(max_length=32)
# 一对多
cid = models.ForeignKey(Class, to_field="id",related_name='class_related')
# 一对一
detail = models.OneToOneField(StudentDetail, to_field="id",related_name='detail_related')

查询：

#正向查询
stu = Student.objects.first()
<Student: 小明>
stu.cid
<Class: 火箭1班>
#反向查询
cls = Class.objects.first()
cls.class_related.all()
<QuerySet [<Student: 小明>, <Student: 小花>, <Student: 小王>]>

效果：

{
      "sname": "小王",
      "cid": {
         "cname": "一班",
         "cdata": "2018-11-17"
      },
      "detail": {
         "height": 180,
         "email": "123@qq.com",
         "memo": "lol"
      }
},
3.多对多对

效果（查询出当前老师的所有班级和对应的班级的所有学生）：

{
      "tname": "王老师",
      "classes": [
         {
            "cname": "一班",
            "class_related": [
                  {
                     "sname": "小王",
                     "detail": {
                        "height": 180,
                        "email": "123@qq.com",
                        "memo": "lol"
                     }
                  }
            ]
         },
         {
            "cname": "二班",
            "class_related": [
                  {
                     "sname": "小刘",
                     "detail": {
                        "height": 175,
                        "email": "234@qq.com",
                        "memo": "dnf"
                     }
                  }
            ]
         },
         {
            "cname": "三班",
            "class_related": [
                  {
                     "sname": "小李",
                     "detail": {
                        "height": 170,
                        "email": "345@qq.com",
                        "memo": "wow"
                     }
                  }
            ]
         },
         {
            "cname": "四班",
            "class_related": [
                  {
                     "sname": "小赵",
                     "detail": {
                        "height": 165,
                        "email": "456@qq.com",
                        "memo": "h1z1"
                     }
                  }
            ]
         }
      ]
},
序列化器：

class StudentsSerializer(serializers.ModelSerializer):
detail = StudentDetailSerializer()

class Meta:
      model = Student
      fields = ('sname','detail')

class ClassSerializer(serializers.ModelSerializer):
#此处可以使用related_name来关联上student表
class_related = StudentsSerializer(many=True)

class Meta:
      model = Class
      fields = ('cname','class_related')

class TeacherSerializer(serializers.ModelSerializer):
classes = ClassSerializer(many=True)

class Meta:
      model = Teacher
      fields = ('tname','classes')
视图：

class TeacherView(GenericAPIView):
serializer_class = TeacherSerializer
queryset = Teacher.objects.all()
# renderer_classes = (Utf8JSONRenderer,)

def get(self, request):
      data = self.get_queryset()
      serializer = self.get_serializer(data, many=True)
      return Response(serializer.data)

作者: 小小不是怪 时间: 2019-1-2 21:08
学习啊啊啊啊啊

作者: 武汉分校-小舞 时间: 2019-1-3 08:56

小小不是怪发表于 2019-1-2 21:08
学习啊啊啊啊啊

作者: 一个人一座城0.0 时间: 2019-2-10 11:27
看一看。

作者: 笨崽崽 时间: 2019-5-27 09:43
6666666666666666666

作者: 2605618480 时间: 2019-5-30 22:31
3414556270

欢迎光临黑马程序员技术交流社区 (http://bbs.itheima.com/)

黑马程序员IT技术论坛 X3.2