CODEWITHSUNDEEP
pythondjangouuidpostgresql-9.4
josephmisiti
josephmisiti

Reputation: 9974

Django UUID field throwing IntegrityError

I added a UUIDField to an existing table as follows (backed by Postgres 9.4):

class MyTable(TimeStampedModel):
    """ """
    ...

    uid = models.UUIDField(default=uuid.uuid4, unique=True,
                editable=False, 
                help_text="Unique identifier")                     
    class Meta:
        app_label = "core"
        db_table = "my_table"
        ordering = ['-created']

And when I run a migration, am seeing the following error which I thought was impossible:

  File "/Users/josephmisiti//projects/xxx/lib/python2.7/site-packages/django/db/backends/base/schema.py", line 398, in add_field
    self.execute(sql, params)
  File "/Users/josephmisiti/projects/xxx/lib/python2.7/site-packages/django/db/backends/base/schema.py", line 111, in execute
    cursor.execute(sql, params)
  File "/Users/josephmisiti/projects/xxx/lib/python2.7/site-packages/django/db/backends/utils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/Users/josephmisiti/projects/xxx/lib/python2.7/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/Users/josephmisiti/projects/xxx/lib/python2.7/site-packages/django/db/utils.py", line 98, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/Users/josephmisiti/projects/xxx/lib/python2.7/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
django.db.utils.IntegrityError: could not create unique index "additional_properties_uid_key"
DETAIL:  Key (uid)=(c0ca7e2a-87de-42d2-b188-14821a0e207a) is duplicated.

I was under the impression that UUIDs were unique and this would never happen - can someone explain why this is not the case! (also, I have seen this before in the past)

Upvotes: 4

Views: 909

Answers (1)

josephmisiti
josephmisiti

Reputation: 9974

The solution I came with was overriding the save method on models.py file:

def save(self, *args, **kwargs):
    if not self.uuid:
        self.uuid = uuid.uuid4()
    super(Model, self).save(*args, **kwargs)

Upvotes: 1

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