On 8/1/07, Kai Kuehne <[EMAIL PROTECTED]> wrote: > > Is this the 'normal' behavior of postgres? I've never used it > before but this seems very odd to me. I'm deleting the whole > database and creating it new every time. After deleting I'm doing this: > > >>> manage.py syncdb > >>> db-dump.py load app > > Do I have to reset the sequences even I created a new > database?
Yes. The problem is cause by the way that Postgres (and Oracle, AFAIK) allocates primary keys. Ordinarily, when you create a new object, you don't specify a primary key - Postgres will allocate a primary key for you. To implement this, Postgres creates a 'sequence' when it creates a table; when you ask for a new object, it allocates the next ID in the sequence. This works fine, until you manually specify a primary key. When you save an object and say "Use PK=3", Postgres doesn't remove 3 from the sequence of allowed primary key values, so if 3 is the next value on the primary key sequence, Postgres will try to use that value to create the object - and fail, because that primary key value is in use. The way you work around the problem is to reset the sequence to Max(PK) after manually specifying a primary key. That way you can be guaranteed that the next sequence will be 1 higher than the currently largest primary key. > (Wondering why there is db-dump.py when dumpdata works.. > but wayne.) It was a snippet project that was started when Django's fixture loading still new and had some problems with edge cases (as I recall, the particular problem was forward references in data). Rather than contribute a fix to Django's fixture loading, limodou decided to start a snippet project to provide an alternate implementation. Since that time, many problems with Django's fixture loader have been fixed (includng the forward reference problem), and there isn't really a need for the alternate implementation. Yours, Russ Magee %-) --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
