David Cramer's Blog - Latest Comments in Improved UUIDField in Django

Re: Improved UUIDField in Django

Your Name — Mon, 22 Nov 2010 16:17:39 -0000

How do you get this to work as the primary_key on an admin inline?

Re: Improved UUIDField in Django

chris — Sat, 08 May 2010 06:38:10 -0000

Thanks for the code. I have a question about getting an object based on the guid field. Here is what I have

from myproj.myapp.models import mymodel
import uuid
u = uuid.UUID('eb7e2cc4-db24-4c3d-b8f6-73bed6468135')
w = mymodel.objects.get(guid=u)

This results in a DoesNotExist exception.

If I change the get_db_prep_value function of UUIDField.py to the following, it works:

def get_db_prep_value(self, value):
if not value: return
assert(isinstance(value, uuid.UUID))
#return unicode(value)
return value.hex

Did I miss something? Is there another way to do this? Thanks.

Re: Improved UUIDField in Django

Andrew Badr — Wed, 21 Apr 2010 20:58:51 -0000

Removed features, and updated for 1.2 and South: http://gist.github.com/374662

Re: Improved UUIDField in Django

Andrew Badr — Tue, 20 Apr 2010 22:12:05 -0000

I'm also using 'uuid', and have the following methods for Django 1.2 support:


    def get_prep_value(self, value):                                                               
        if not value:                                                                              
            return
        assert(isinstance(value, uuid.UUID))                                                       
        return value.hex                                                                           
    
    def get_prep_lookup(self, lookup_type, value):                                                 
        if lookup_type == 'exact':                                                                 
            return value.hex
        elif lookup_type == 'in':
            return [u.hex for u in value]
        raise ValueError, "UUIDField does not support '%s' queries" % lookup_type

edit: see my other post for full solution

Re: Improved UUIDField in Django

David Underhill — Thu, 28 Jan 2010 15:06:23 -0000

Thanks for sharing - this code works well for me! I'm also experimenting with just using a regular CharField and auto-populating the value using a post_init signal handler.

Re: Improved UUIDField in Django

EdMenendez — Thu, 25 Jun 2009 20:54:29 -0000

I'm using the following for Postgres 8.2.

def db_type(self):
return 'character varying(32)'

def get_db_prep_value(self, value):
if not value: return
if not isinstance(value, uuid.UUID):
value = uuid.UUID(value)
return value.hex #unicode(value)

Re: Improved UUIDField in Django

HenrikV — Tue, 24 Mar 2009 19:08:56 -0000

I originally started out using UUID as primary keys on my old project. I had some trouble with uuid imports in Python 2.5

I seem to recall that if you for some reason try to import uuid in settings.py python will silently crash.

Did you have any trouble like that?

Re: Improved UUIDField in Django

Joe — Wed, 11 Mar 2009 23:57:19 -0000

Ah, sorry, I need varchar(length) on Postgres... but it supports uuid anyway, so I'm using ---

def db_type(self):
return 'uuid'

Although it seems (for me, at least) that get_db_prep_value assumes it's dealing with a uuid.UUID, when in the admin change view it's a unicode (and postgresql and other DBs seemingly want a 36 char string anyway...) so I'm using the following,

def get_db_prep_value(self, value):
if not value: return
print type(value)
if isinstance(value, uuid.UUID):
return unicode(value)
return value

Re: Improved UUIDField in Django

Joe — Wed, 11 Mar 2009 22:52:43 -0000

Yeah, for some reason my __init__ doesn't seem to be called in trunk.

In other words with,

class MyModel(models.Model):
uuid = UUIDField(primary_key=True, db_index=True, auto=True)

I get a character(1) in my DB (postgresql) and thus everything fails... so weird. I can even import the class and UUIDField() with a 1/0 in the init and nothing happens? I assume this has to do with the metaclass or something?

Re: Improved UUIDField in Django

David Cramer — Tue, 10 Mar 2009 15:01:49 -0000

Sorry the original code has been fixed.

However, there seems to be an issue in Django where it's not quite passing in UUID instances everywhere. I'm currently looking into why.

Re: Improved UUIDField in Django

Joe — Sun, 08 Mar 2009 12:42:38 -0000

What is the variable "name" here (undefined)?

elif version in (3, 5):
self.namespace, self.name = namespace, name

Re: Improved UUIDField in Django

trbs — Tue, 03 Mar 2009 05:15:18 -0000

Any patched for useful improvements to the UUIDField in django-extensions would be much appreciated :)

Re: Improved UUIDField in Django

skabber — Mon, 02 Mar 2009 13:36:31 -0000

Very nice. Do you know how this compares to the UUIDField in django extensions?

http://code.google.com/p/dj...

Re: Improved UUIDField in Django

Brantley Harris — Mon, 02 Mar 2009 11:24:58 -0000

Careful, the uuid module is not in 2.4 or below.

Re: Improved UUIDField in Django

at9t — Sun, 01 Mar 2009 08:52:57 -0000

This one seems useful, thanks!

Re: Improved UUIDField in Django

Josh — Sat, 28 Feb 2009 20:34:55 -0000

ah, good point. I was thinking in terms of using a UUIDField as a model's PK, without considering FK scenarios. Thanks again!

Re: Improved UUIDField in Django

David Cramer — Sat, 28 Feb 2009 20:22:12 -0000

No because it could just be a ForeignKey reference.

Re: Improved UUIDField in Django

Josh — Sat, 28 Feb 2009 20:18:16 -0000

Interesting snippet!! Thanks for sharing.

One question: shouldn't "kwargs['unique'] = True" be outside of the "if self.auto:" block?