base.py 文件源码

def _check_id_field(cls):
        """ Check if `id` field is a primary key. """

        fields = list(f for f in cls._meta.local_fields
            if f.name == 'id' and f != cls._meta.pk)
        # fields is empty or consists of the invalid "id" field
        if fields and not fields[0].primary_key and cls._meta.pk.name == 'id':
            return [
                checks.Error(
                    "'id' can only be used as a field name if the field also "
                    "sets 'primary_key=True'.",
                    hint=None,
                    obj=cls,
                    id='models.E004',
                )
            ]
        else:
            return []