> > UUIDs are your best bet. Even if you generated 100 billion UUIDs a > second for the next 100 years, the chance of one collision would only > be 50% [1]. > > class ProducedEntity(models.Model): > .... > uuid = models.CharField(max_length=36, unique=True) > > def _hook_add_uuid(instance, sender, **kwargs): > import uuid > if not hasattr(instance, 'uuid') or not instance.uuid: > instance.uuid = str(uuid.uuid4()) > > from django.db.models.signals import pre_save > pre_save.connect(_hook_add_uuid, sender=ProducedEntity) > > UUIDs can be stored more efficiently than that, its just a big 128 bit > number, so can be stored as 2 long integers. See your DB manual for > more info. > > Cheers > > Tom > > [1]http://en.wikipedia.org/wiki/Universally_unique_identifier#Random_UUI...
First of all to everyone, thanks for all good suggestions so far. Regarding UUIDs, one of the business requirements (which I don't control) is that the identifier that is to be used on barcodes and what not is to be in the format "YYMMDDXXXX" where XXXX is the number we are talking about. So UUID would be great and unique, as well would the automatic pk/id from the model itself as that is unique enough. But I need a rolling number per day and nothing else. -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-us...@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
