Re: transactions and unique variables:
Tim Chase wrote:
> Which follows the pattern
>
>UPDATE tbl
>SET field = (
> SELECT SUM(field)
> FROM tbl
> WHERE [EMAIL PROTECTED] or [EMAIL PROTECTED]
> ) - field
>WHERE [EMAIL PROTECTED] or [EMAIL PROTECTED]
>
> Any help?
>
> -tkc (aka "the atomic swapper"? :)
Hehehe, that's a pretty neat trick... Could you write that in django ORM
for me? ;-)))
Seeing I only need to do this very infrequently, I think I'll just do
the 3 saves...
tmp = items.__class__.order_by("-field")[0].field + 1
tmp, i1.field = i1.field, tmp
i1.save()
i1.field, i2.field = i2.field, tmp
i2.save()
i1.save()
ugly, but gets the job done...
- bram
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Re: transactions and unique variables:
> Uhm, please ignore this email, it looks like this can't be done using > transactions > > begin transaction; > update book set "order"=2 where id=1; > update book set "order"=1 where id=2; > commit; for atomic swapping, however, it can be done in a single obscure SQL statement: update book set order = 3 - order where id=1 or id=2 Which follows the pattern UPDATE tbl SET field = ( SELECT SUM(field) FROM tbl WHERE [EMAIL PROTECTED] or [EMAIL PROTECTED] ) - field WHERE [EMAIL PROTECTED] or [EMAIL PROTECTED] Any help? -tkc (aka "the atomic swapper"? :) --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Re: transactions and unique variables:
Bram - Smartelectronix wrote: > Rubic wrote: >> Bram, >> >> Try removing (commenting out) the transaction decorator >> and transaction.commit(), then re-run your code. The >> ProgrammingError exception may be hiding the real >> exception. At least that's been my experience. > > Nope..., I'm really getting the "unique key violation" on order... Uhm, please ignore this email, it looks like this can't be done using transactions begin transaction; update book set "order"=2 where id=1; update book set "order"=1 where id=2; commit; ERROR: duplicate key violates unique constraint "book_order_key" What a pitty! - bram --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Re: transactions and unique variables:
Rubic wrote: > Bram, > > Try removing (commenting out) the transaction decorator > and transaction.commit(), then re-run your code. The > ProgrammingError exception may be hiding the real > exception. At least that's been my experience. Nope..., I'm really getting the "unique key violation" on order... - bram --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Re: transactions and unique variables:
Bram, Try removing (commenting out) the transaction decorator and transaction.commit(), then re-run your code. The ProgrammingError exception may be hiding the real exception. At least that's been my experience. -- Jeff Bauer Rubicon, Inc. --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
