Django之同时新增数据到两个数据库表与同时返回两个表的数据(插拔式)，

Django之同时新增数据到两个数据库表与同时返回两个表的数据(插拔式)，

• models：比如有以下三个模型

from django.db import models

"""
基类，其他类继承即可获得对应的字段
""" 
class BaseModel(models.Model):
    updated_tm = models.DateTimeField(auto_now=True)
    created_tm = models.DateTimeField(auto_now_add=True)

    class Meta:
        abstract = True

"""
项目列表
"""
class ProjectList( BaseModel):
    project_id = models.AutoField(help_text="项目ID", primary_key=True)
    project_name = models.SlugField(max_length=128, help_text="项目名称", unique=True)

    class Meta:
        db_table = 'project_list'
        verbose_name = '项目列表信息'
        verbose_name_plural = verbose_name

"""
项目详情
"""
class ProjectDetail(BaseModel):
    project_introduction = models.CharField(max_length=128, help_text="用户简介")
    project_info = models.ForeignKey(to=ProjectList, on_delete=models.DO_NOTHING, db_constraint=False, related_name='user')

    class Meta:
        db_table = project_detail'
        verbose_name = '项目详情信息'
        verbose_name_plural = verbose_name

一、同时新增数据到两个数据库表

• views

from rest_framework import filters, mixins, generics
from rest_framework.viewsets import GenericViewSet


class ProjectListView(mixins.CreateModelMixin, GenericViewSet):
    queryset = Account.objects.filter(is_delete=0).all().order_by("-created_tm")

def create(self, request, *args, **kwargs):
    # 先定义两个dict 
    project_list_dict = {}
    project_detail_dict = {}

    # 使用 ._meta.get_fields() 获取数据库表的全部字段，再使用field.name获取全部的字段名称，放入各自的dict，不存在的自动忽略掉
    for item in request.data.items():
        if item in [field.name for field in ProjectList._meta.get_fields()]:
            project_list_dict [item[0]] = item[1]
        elif item in [field.name for field in ProjectDetail._meta.get_fields()]:
            project_detail_dict [item[0]] = item[1]

    # 从上面的models可以看到，项目详情与项目列表两张表是有关联的，所以，新增数据的时候，先现在列表，新增成功，生成ID后，再新增详情，并通过ID与列表数据关联起来
    # 检查项目是否存在，项目名称唯一约束，Serializer内设置必填
        try:
            # 存在就直接失败
            ProjectList.objects.get(project_name=request.data.get('project_ame'))
            return xxx
        except Account.DoesNotExist:
            # 如果不存在，先调用ProjectList表新增数据
            try:
                project_create = ProjectList.objects.update_or_create(defaults=project_list_dict, project_name=project_list_dict["project_ame"])
                # 如果ProjectList表新增数据成功，则通过project_info，在ProjectDetail新增对应的数据
                if project_create:
                    project_id = ProjectList.objects.filter(project_name=project_list_dict["project_ame"]).values('project_id').first()
                    ProjectDetail.objects.update_or_create(defaults=project_detail_dict, project_info=project_id["project_id"])
                    return xxx
            except Exception as e:
                return e

二、同时返回两个表的数据(插拔式)

• 插拔式的好处：即插即用，需要时才调用，不需要则不调用
• 从ProjectDetail这个models我们可以看到，是没有定义project_id和project_name的，但我们是与ProjectList关联的，所以，我们可以通过project_info，返回ProjectList已定义的project_id和project_name

# 我们只需要把ProjectDetail改成以下这样子就可以了
class ProjectDetail(BaseModel):
    project_introduction = models.CharField(max_length=128, help_text="用户简介")
    project_info = models.ForeignKey(to=ProjectList, on_delete=models.DO_NOTHING, db_constraint=False, related_name='user')

    class Meta:
        db_table = project_detail'
        verbose_name = '项目详情信息'
        verbose_name_plural = verbose_name

    @property
    def  project_id(self):
        return self.project_info.project_id

    @property
    def  project_name(self):
        return self.project_info.project_name

# 然后在序列化器内直接调用project_id和project_name即可
class ProjectDetailSerializer(serializers.ModelSerializer):
    class Meta:
        model = ProjectDetail

        fields = ('project_id', 'project_name', 'project_introduction',)