CODEWITHSUNDEEP
djangopostgresql
h1dd3n
h1dd3n

Reputation: 292

Django ContentTypes convert uuid field to integer field

I have a situation where object_id for ForeignKey accepts a PositiveIntegerField but all id's of my models are set as uuid .

I looked up the documentation and found that i should use get_prep_value(value) or get_db_prep_value(value, connection, prepared=False)¶

The question is how should i exactly do it?

Here is the code of model that contains the foreignRelation

target_ct = models.ForeignKey(ContentType,
                              blank=True,
                              null=True,
                              related_name='target_obj',
                              on_delete=models.CASCADE)
target_id = models.PositiveIntegerField(null=True,
                                        blank=True,
                                        db_index=True)
target = GenericForeignKey('target_ct', 'target_id')

created_at = models.DateTimeField(auto_now_add=True,
                                  db_index=True)

Field from all other models

id = models.UUIDField(default=uuid4, primary_key=True, editable=False)

Whenever i try to save the model with the current setting i get this error

django.db.utils.DataError: integer out of range

Upvotes: 2

Views: 1155

Answers (1)

willeM_ Van Onsem
willeM_ Van Onsem

Reputation: 476584

You make it a UUIDField as well:

class MyModel(models.Model):
    target_ct = models.ForeignKey(
        ContentType,
        blank=True,
        null=True,
        related_name='target_obj',
        on_delete=models.CASCADE
    )
    target_id = models.UUIDField(
        null=True,
        blank=True,
        db_index=True
    )
    target = GenericForeignKey('target_ct', 'target_id')
    created_at = models.DateTimeField(auto_now_add=True, db_index=True)

Then you this can refer to all objects that have a UUIDField as primary key.

Exactly this is however one of the reasons why it is often better to use an AutoField as primary key: if all models have the same primary key you can refer to all objects with this. Now with this you can only refer to models with a UUIDField as primary key.

Upvotes: 4

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