I'm also +1 __nonezero__ -1 .exists(). Using .count() already gives us the required functionality and makes logical sense, the only question then is how big of a performance gain do we get by using SELECT 1 LIMIT 1.
SELECT 1 FROM [table] LIMIT 1 also feels kinda hackish to me, and I'm guessing it's likely not supported in all database engines used by Django and/or is not the most efficient statement in all supported engines, in which case .exists() would only become a performance workaround for some engines and either using .count() or simply having .exists() as an alias to .count() for those engines where count(*) or count(pk) is most efficient. I'd rather petition the PostgreSQL developers to optimise count(*) and suggest Django users implement their own changes or workaround in the meantime if they're working with large datasets where count(*) is a serious performance penalty. I like Malcom's idea of just checking the first value in a queryset to save a second SQL statement, but I'm not sure it would be appropriate in all cases. There may be times when people *just* want to check if records exist, without actually selecting or iterating through records. In those cases wouldn't it be more efficient to do a single .count() than selecting all your records and only returning the first one? --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django developers" group. To post to this group, send email to django-developers@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-developers?hl=en -~----------~----~----~----~------~----~------~--~---
