python - DjangoForeignKey self 条件

Question

我有一个模型，其中每个角色都有“母亲”和“父亲”字段。它们是FroeignKey，指的是self。我想为性别设置条件，“F”、“女”为母字段，“H”、“男”为父字段。

class Character(models.Model):
    H = 'Male'
    F = 'Female'
    GENDER_CHOICES = (
        (H, 'Male'),
        (F, 'Female'),
    )
    
    last_name = models.fields.CharField(max_length=100)
    first_name = models.fields.CharField(max_length=100)
    gender = models.CharField(max_length=30, choices=GENDER_CHOICES, null=True, blank=True)
    mother = models.ForeignKey('self', blank=True, null=True, on_delete=models.SET_NULL, related_name='linkmother')
    father = models.ForeignKey('self', blank=True, null=True, on_delete=models.SET_NULL, related_name='linkfather')
    date_birth = models.DateField(default=date.today, null=True, blank=True)
    date_death = models.DateField(default=date.today, null=True, blank=True)

    def __str__(self):
        return f'{self.first_name} {self.last_name}'

Answer 1

您可以使用 limit_choices_to=… parameter ^{[Djangod-doc]} :

class Character(models.Model):
    H = 'Male'
    F = 'Female'
    # …
    gender = models.CharField(
        max_length=30,
        choices=GENDER_CHOICES,
        null=True,
        blank=True
    )
    # …
    mother = models.ForeignKey(
        'self',
        blank=True,
        null=True,
        on_delete=models.SET_NULL,
        related_name='children_as_mother',
        <strong>limit_choices_to={'gender': F}</strong>
    )
    father = models.ForeignKey(
        'self',
        blank=True,
        null=True,
        on_delete=models.SET_NULL,
        related_name='children_as_father',
        <strong>limit_choices_to={'gender': H}</strong>
    )
    # …