Django DB 模型，创建两个相同的表，一个从另一个继承

Question

我有一个要求，我想在 Django 中拥有相同的表。例如 MyTableCurrent 和 MyTableArchive。

除了类/表名和外键引用之外，这些表应该是相同的。

有没有办法基本上维护 MyTableCurrent 上的架构，然后在 MyTableArchive 下，我继承自 MyTableCurrent 的基类，但只覆盖外键字段以匹配相应的存档表？

Answer 1

我找到了我正在寻找的解决方案。

https://docs.djangoproject.com/en/2.1/topics/db/models/#abstract-base-classes

class ServiceProviderBase(models.Model):
    sp_id = models.CharField(max_length=64, primary_key=True)
    name = models.CharField(max_length=64, null=True, blank=True)
    isEnterprise = models.CharField(max_length=5)
    cluster = models.CharField(max_length=64)
    created_date = models.DateTimeField(auto_now_add=True)

    class Meta:
        abstract = True


class ServiceProviderCurrent(ServiceProviderBase):
    pass


class ServiceProviderArchive(ServiceProviderBase):
    pass


class GroupBase(models.Model):
    id = models.AutoField(primary_key=True)
    grp_id = models.CharField(max_length=64)
    name = models.CharField(max_length=64, null=True, blank=False)
    userLimit = models.IntegerField()
    organizationType = models.CharField(max_length=64)
    created_date = models.DateTimeField(auto_now_add=True)

    class Meta:
        abstract = True


class GroupCurrent(GroupBase):
    organizationId = models.ForeignKey('sandbox.ServiceProviderCurrent', on_delete=models.CASCADE)


class GroupArchive(GroupBase):
    organizationId = models.ForeignKey('sandbox.ServiceProviderArchive', on_delete=models.CASCADE)

Answer 2

您可以创建一个表和从该表继承的其他两个表。示例：

class BaseMedal(models.Model):
  field_one = models.ForeignKey(TableName,...)
  field_two = models.ForeignKey(AnotherTableName,...)

class ModelOne(BaseModal)
  field = models.TextField(...)

class ModelTwo(BaseModel)
  field = models.TextField(...)

这样，ModelOne 和 ModelTwo 的外键字段是相同的。

Answer 3

您可以使用Proxy Model。例如：

class BaseModel(models.Model):
    # your common fields


class Current(BaseModel):
     class Meta:
         proxy=True

     def some_current_model_method(self):
         # specific method for this class

class Archive(BaseModel):
     class Meta:
         proxy=True

     def some_archive_model_method(self):
         # specific method for this class

更新

用法：

archive1 = Archive.objects.create(title="Archive 1")
archive2 = Archive.objects.create(title="Archive 2")
current1 = Current.objects.create(title="Current 1")
current2 = Current.objects.create(title="Current 2")


archives = Archive.objects.all().count()  # will print 4
currents = Current.objects.all().count()  # will print 4
base = BaseModel.objects.all().count()  # print 4


Archive.objects.get(title="Archive 1")  # will work
Archive.objects.get(title="Current 1")  # will work

Current.objects.get(title="Archive 1")  # will work
Current.objects.get(title="Current 1")  # will work

BaseModel.objects.get(title="Archive 1")  # will work
BaseModel.objects.get(title="Current 1")  # will work

BaseModel.objects.create(title="BaseModel")
Archive.objects.get(title="BaseModel")  # will work
Current.objects.get(title="BaseModel")  # will work