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在子类唯一\u together元选项中使用基类字段时出错

django-models django

Eric Acevedo · 技术社区 · 14 年前

使用以下代码:

class Organization(models.Model):
    name = models.CharField(max_length="100",)
    alias = models.SlugField()
    ...

class Division(Organization):
    parent_org = models.ForeignKey(Organization)

    class Meta:
        unique_together=['parent_org', 'alias']
        ...

尝试同步数据库时出错:

Error: One or more models did not validate:
organizations.division: "unique_together" refers to alias. This is not in the 
same model as the unique_together statement.

感谢您的帮助,

谢谢,

埃里克

4 回复 | 直到 11 年前

Pewpewarrows 14 年前

unique_together

[field]_ptr_id [field] organization_ptr_id

unique_together UNIQUE

Validators

Model Validators validate_unique

Jameson Quinn 14 年前

class BaseOrganization(models.Model):
    name = models.CharField(max_length="100",)
    alias = models.SlugField()
    class Meta:
        abstract = True

class Organization(BaseOrganization):
    pass

class Division(BaseOrganization):
    parent_org = models.ForeignKey(Organization)

    class Meta:
        unique_together=['parent_org', 'alias']

Richard 11 年前

unique_together

class Meta():
    abstract = True

单桅帆船 可能是因为所有字段都在同一个表中。

https://docs.djangoproject.com/en/1.5/topics/db/models/#abstract-base-classes

user2994322 11 年前

这是我最近在Django 1.6中使用的解决方案(感谢Manoj Govindan的想法):

class Organization(models.Model):
    name = models.CharField(max_length="100",)
    alias = models.SlugField()
    ...

class Division(Organization):
    parent_org = models.ForeignKey(Organization)

    # override Model.validate_unique
    def validate_unique(self, exclude=None):     
        # these next 5 lines are directly from the Model.validate_unique source code
        unique_checks, date_checks = self._get_unique_checks(exclude=exclude)
        errors = self._perform_unique_checks(unique_checks)
        date_errors = self._perform_date_checks(date_checks)
        for k, v in date_errors.items():
            errors.setdefault(k, []).extend(v)

        # here I get a list of all pairs of parent_org, alias from the database (returned 
        # as a list of tuples) & check for a match, in which case you add a non-field 
        # error to the error list
        pairs = Division.objects.exclude(pk=self.pk).values_list('parent_org', 'alias')
        if (self.parent_org, self.alias) in pairs:
                errors.setdefault(NON_FIELD_ERRORS, []).append('parent_org and alias must be unique')

        # finally you raise the ValidationError that includes all validation errors, 
        # including your new unique constraint
        if errors:
            raise ValidationError(errors)