NOT NULL约束失败：courses_app_branch.course_id

Question

当我在RESTful API中请求POST方法时，我的course_id中的BranchSerializer有问题。 所有答案都提前感谢！

代码示例serializers.py：

class BranchSerializer(serializers.ModelSerializer):
    class Meta:
        model = Branch
        fields = ('address', 'latitude', 'longitude')


class ContactSerializer(serializers.ModelSerializer):
    class Meta:
        model = Contact
        fields = ('type', 'value')


class CourseSerializer(serializers.ModelSerializer):
    branches = BranchSerializer(many=True, required=False)
    contacts = ContactSerializer(many=True, required=False)

    def create(self, validated_data):
        if 'branches' in validated_data:
            branches_data = validated_data.pop('branches')
        if 'contacts' in validated_data:
            contacts_data = validated_data.pop('contacts')
        course = Course.objects.create(**validated_data)
        branches_list = []
        contacts_list = []
        print(contacts_data)
        print(branches_data)
        for branches_details in branches_data:
            branches_list.append(Branch.objects.create(
            course_id = course.id,
            **branches_details))
        for contacts_details in contacts_data:
            contacts_list.append(Contact.objects.create(
            course_id = course.id,
            **contacts_details))
        course.save()
        return course

Models.py：

class Branch(models.Model):
    course = models.ForeignKey(Course, on_delete=models.CASCADE, related_name="branches")
    latitude = models.TextField()
    longitude = models.TextField()
    address = models.TextField()

    def __str__(self):
        return str(self.address)

  

没有NULL约束失败：courses_app_branch.course_id