Django DRY模型

Question

一般来说，当我不得不多次重复几个属性时，我如何保持模型干燥？

例如：

class Event(models.Model):
    title = models.CharField(max_length=255)
    postal_code = models.CharField(max_length=5)
    city = models.CharField(max_length=50)
    street = models.CharField(max_length=50)
    street_nr = models.CharField(max_length=5)

class Person(models.Model):
    name = models.CharField(max_length=50)
    postal_code = models.CharField(max_length=5)
    city = models.CharField(max_length=50)
    street = models.CharField(max_length=50)
    street_nr = models.CharField(max_length=5)

Answer 1

规范化您的数据库结构，您可以进一步规范化地址

class Adress(models.Model):
    postal_code = models.CharField(max_length=5)
    city = models.CharField(max_length=50)
    street = models.CharField(max_length=50)
    street_nr = models.CharField(max_length=5)

class Event(models.Model):
    title = models.CharField(max_length=255)
    address = models.ForeignKey(Adress, on_delete=models.CASCADE)

class Person(models.Model):
    name = models.CharField(max_length=50)
    address = models.ForeignKey(Adress, on_delete=models.CASCADE)

Answer 2

只需添加引用：

class AdressData(models.Model):
    postal_code = models.CharField(max_length=5)
    city = models.CharField(max_length=50)
    street = models.CharField(max_length=50)
    street_nr = models.CharField(max_length=5)

class Event(models.Model):
    title = models.CharField(max_length=255)
    address_data = models.ForeignKey('AdressData')

class Person(models.Model):
    name = models.CharField(max_length=50)
    address_data = models.ForeignKey('AdressData')

Answer 3

Django模型可以使用Python的对象继承来共享公共数据；但有一个规定。这些被称为abstract models。

为了使用抽象模型重构你的代码，我会这样写它：

class BaseAddressModel(models.Model):
    postal_code = models.CharField(max_length=5)
    city = models.CharField(max_length=50)
    street = models.CharField(max_length=50)
    street_nr = models.CharField(max_length=5)

    class Meta:
        abstract = True


class Event(BaseAddressModel):
    title = models.CharField(max_length=255)


class Person(BaseAddressModel):
    name = models.CharField(max_length=50)

前面的答案可能会更好地满足您的目的，但这是一个选择。