[sqlalchemy] Re: Query objects and empty slices
Michael Bayer [EMAIL PROTECTED] writes: yes. but the question was, limit is ignored when offset is zero, which is not the issue. LIMIT is ignored when its zero, period (it evaluates to false). the decision to be made is, should Query circumvent querying altogether when limit is zero. this will be easy to fix in 0.5 since slices will no longer be generative, so we'll just return an empty iterator. ticket 1035 in trac. Sounds good. Keep up the good work. -- Yannick Gingras --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Query objects and empty slices
On May 10, 2008, at 10:22 AM, Yannick Gingras wrote: I attach a test case. In here, it prints: -- ** q[:0] SELECT users.id AS users_id, users.name AS users_name FROM users ORDER BY users.id ** q[0:0] SELECT users.id AS users_id, users.name AS users_name FROM users ORDER BY users.id ** q[1:1] SELECT users.id AS users_id, users.name AS users_name FROM users ORDER BY users.id LIMIT 0 OFFSET 1 ** q[0:10] SELECT users.id AS users_id, users.name AS users_name FROM users ORDER BY users.id LIMIT 10 OFFSET 0 -- Shouldn't the first two feature LIMIT 0 OFFSET 1? yes. but the question was, limit is ignored when offset is zero, which is not the issue. LIMIT is ignored when its zero, period (it evaluates to false). the decision to be made is, should Query circumvent querying altogether when limit is zero. this will be easy to fix in 0.5 since slices will no longer be generative, so we'll just return an empty iterator. ticket 1035 in trac. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Query objects and empty slices
On May 2, 2008, at 6:33 AM, Yannick Gingras wrote: My guess is that the underlying Select object does not take limit into account when offset is 0. you mean, a limit of zero itself is ignored. an offset of zero doesn't affect limit. You will all agree that this is a bug and that it needs to be fixed. I don't mind digging into the sources to fix it. Can anyone point me in the right direction? if the limit is zero Id imagine that no SQL would be issued at all. do you agree ? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Query objects and empty slices
Michael Bayer [EMAIL PROTECTED] writes: My guess is that the underlying Select object does not take limit into account when offset is 0. you mean, a limit of zero itself is ignored. an offset of zero doesn't affect limit. When _offset is 0 or None, _limit seems to be ignored. There might be something else but I see: print q[:0] # no limit statement in the SQL print q[0:0] # no limit statement in the SQL print q[1:1] # limit statement is there You will all agree that this is a bug and that it needs to be fixed. I don't mind digging into the sources to fix it. Can anyone point me in the right direction? if the limit is zero Id imagine that no SQL would be issued at all. do you agree ? That's one way to see it and it would make sense. However, issuing the query anyway validates that aside from returning nothing, all the selected tables are there. My preference goes for returning an empty list without emitting SQL. -- Yannick Gingras --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Query objects and empty slices
On May 2, 2008, at 10:52 AM, Yannick Gingras wrote: When _offset is 0 or None, _limit seems to be ignored. There might be something else but I see: print q[:0] # no limit statement in the SQL print q[0:0] # no limit statement in the SQL print q[1:1] # limit statement is there the first two have a LIMIT of zero. Did you try: print q[0:10] ? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
