备份问题-原生问题

class SerialierTeacherClass(serializers.ModelSerializer):

    teacher_ids=serializers.ListField(
        child=serializers.IntegerField(),allow_empty=False
        ,write_only=True
    )

    classid=serializers.SerializerMethodField(read_only=True)
    teacher_id=serializers.SerializerMethodField(read_only=True)
    class Meta:
        model = models.TeacherClass
        fields = ["class_id","teacher_id","teacher_ids","classid"]
        extra_kwargs={
            "teacher_id":{"read_only":True},
            "class_id":{"write_only":True}
        }

    def get_classid(self,queryset):
        if isinstance(queryset,list):
            sets=set()
            for obj in queryset:
               sets.add(obj.class_id)
            return list(sets)
    def get_teacher_id(self,queryset):
        if isinstance(queryset,list):
            sets=set()
            for obj in queryset:
               sets.add(obj.teacher_id)
            return list(sets)





    def create(self, validated_data):
       # todo  default for  update  args ,**kwargs is for filter
       teacher_ids=validated_data.pop("teacher_ids")
       bulks=[]
       for teacher_id in teacher_ids:
          teacher_class_object=TeacherClass(teacher_id=teacher_id,**validated_data)
          bulks.append(teacher_class_object)
       objs=TeacherClass.objects.bulk_create(bulks)
       return objs

　

模型：

class  TeacherClass(models.Model):
    teacher_id =models.IntegerField(max_length=200)
    class_id =models.IntegerField()
    is_delete = models.BooleanField(default=False)

    class Meta :
        db_table="tbl_teacher_class"
        verbose_name="老师表"
        # unique_together=("class_id","teacher_id")

　

第二种：

以list形式存储某个字段：

比如前端传参数老师id为数组存在tbl_teacher_class：

{

    "teacher_ids": [1,2],

    "class_id": 1

}

class SerialierTeacherClass(serializers.ModelSerializer):

    teacher_id=serializers.ListField(
        child=serializers.IntegerField(),allow_empty=False

    )
    class Meta:
        model = models.TeacherClass
        # fields = ["class_id","teacher_id","teacher_ids","classid"]
        fields = ["class_id", "teacher_id"]
        extra_kwargs={

        }


    def create(self, validated_data):
       # todo  default for  update  args ,**kwargs is for filter
       obj,created_status=TeacherClass.objects.update_or_create(defaults=validated_data,**validated_data)
       return obj

　模型：

class  TeacherClass(models.Model):
    teacher_id =models.CharField(max_length=100)
    class_id =models.IntegerField()
    is_delete = models.BooleanField(default=False)

    class Meta :
        db_table="tbl_teacher_class"
        verbose_name="老师表"
        # unique_together=("class_id","teacher_id")

　

relation关联减少重复数据问题：

class SerializerTeacher(serializers.ModelSerializer):
    class Meta:
        model = models.Teacher
        fields = "__all__"


class SerializerStudent(serializers.ModelSerializer):
    """
    # serializers_class=SerializerClass(instance=class_object,many=False)
    # res.append(serializers_class.data)
    """
    user_sex = serializers.CharField(source="get_sex_display", read_only=True)
    class_info = serializers.SerializerMethodField(read_only=True)
    teachers = serializers.SerializerMethodField(read_only=True)

    class Meta:
        model = models.Student
        fields = ["id", "class_id", "sex", "class_info", "user_sex", "name", "teachers"]
        extra_kwargs = {
            "id": {"read_only": True},
            "sex": {"write_only": True},
            "is_delete": {"write_only": True}
        }

    def get_class_info(self, object):
        class_queryset = models.Class.objects.filter(id__exact=object.class_id).all()
        res = [class_object.cname for class_object in class_queryset]
        return res

    def get_teachers(self, object):
        teacher_ids = TeacherClass.objects.filter(class_id__exact=object.class_id).all().values("teacher_id")
        # todo can filter by  queryset
        teacher_queryset = models.Teacher.objects.filter(id__in=teacher_ids).all()

        res = [item.tname for item in teacher_queryset]
        return res


class SerializerClass(serializers.ModelSerializer):
    class Meta:
        model = models.Class

        fields = ["id", "cname", "create_time", "update_time", "is_delete"]
        extra_kwargs = {
            "id": {"read_only": True},
            "is_delete": {"write_only": True},

        }



class  SerialierTeacherClass(serializers.ModelSerializer):

    class Meta:
        model = models.TeacherClass
        fields = ["class_id", "teacher_id"]


    def create(self, validated_data):
        obj,is_create=TeacherClass.objects.get_or_create(defaults=validated_data,**validated_data)
        return obj

　

模型：

from django.db import models


class Teacher(models.Model):
    tname=models.CharField(max_length=30,error_messages={"required":True},unique=True)
    address=models.CharField(200,max_length=100)
    age=models.IntegerField(default=18)
    is_delete=models.BooleanField(default=False)
    class Meta :
        db_table="tbl_teacher"
        verbose_name="老师表"

class Class(models.Model):
    cname = models.CharField(max_length=32,unique=True)
    create_time= models.DateField(auto_now_add=True,null=True)
    update_time=models.DateField(auto_now=True,null=True)
    is_delete=models.BooleanField(default=False)


    def __str__(self):
        return self.cname

    class Meta :
        db_table="tbl_class"
        verbose_name="老师表"

class Student(models.Model):
    """ 注意一对一反向查询和多对一有区别"""
    name = models.CharField(max_length=32,unique=True)
    sex_choice=[(0,"男"),(1,"女")]
    sex=models.IntegerField(choices=sex_choice,verbose_name="性别",error_messages={"required":True})
    class_id =models.PositiveIntegerField()
    is_delete=models.BooleanField(default=False)

    class Meta :
        db_table="tbl_student"
        verbose_name="学生表"

class  TeacherClass(models.Model):
    teacher_id =models.IntegerField(max_length=100)
    class_id =models.IntegerField()
    is_delete = models.BooleanField(default=False)

    class Meta :
        db_table="tbl_teacher_class"
        verbose_name="老师表"
        # unique_together=("class_id","teacher_id")