Question

我有4个django模型：

class KeyOne(models.Model):
    name = models.CharField(unique=True)

class KeyTwo(models.Model):
    name = models.CharField(unique=True)

class KeyThree(models.Model):
    name = models.CharField(unique=True)

class KeyList(models.Model):
    key_one = models.ForeignKey(KeyOne)
    key_two = models.ForeignKey(KeyTwo)
    key_three = models.ForeignKey(KeyThree)
    list = models.CharField()

基本上，KeyList是与KeyOne，KeyTwo和KeyThree的不同组合相关联的关键字列表。如何确保在Django Admin中只能输入唯一的组合？

Answer 1

您必须在KeyList中设置Meta类：

class KeyList(models.Model):
    key_one = models.ForeignKey(KeyOne)
    key_two = models.ForeignKey(KeyTwo)
    key_three = models.ForeignKey(KeyThree)
    list = models.CharField()
    class Meta:
        unique_together = (("key_one", "key_two", "key_three"),)

Answer 2

Django> 2.2

Django文档说：

改为使用UniqueConstraint与Constraints选项。 UniqueConstraint提供的功能比unique_together还要多。将来可能不推荐使用unique_together。

所以在您的情况下：

class KeyList(models.Model):
    key_one = models.ForeignKey(KeyOne)
    key_two = models.ForeignKey(KeyTwo)
    key_three = models.ForeignKey(KeyThree)
    list = models.CharField()
    class Meta:
        constraints = [
            models.UniqueConstraint(fields=["key_one", "key_two", "key_three"], name="all_keys_unique_together")
]

Django独特的外键组合

2 个答案: