Re: Help with exclusion constraint - Mailing list pgsql-general

From Moshe Jacobson
Subject Re: Help with exclusion constraint
Date
Msg-id CAJ4CxL=0iDwJP8DoNpMdkYyE8enV_6wWdRL__3q96nzS2FqP_Q@mail.gmail.com
Whole thread Raw
In response to Re: Help with exclusion constraint  (hari.fuchs@gmail.com)
List pgsql-general

On Fri, Mar 28, 2014 at 12:45 PM, <hari.fuchs@gmail.com> wrote:
> I want to ensure that for any given value of fk_col that there is a maximum
> of one row with bool_col = true.

This should be what you want:

ALTER TABLE exclusion_example
ADD CONSTRAINT ex
EXCLUDE (fk_col WITH =) WHERE (bool_col);

Yes, that would do the trick! 
I think I'll just set up a partial unique index as per Igor's suggestion, however.

Thank you!

Moshe Jacobson
Manager of Systems Engineering, Nead Werx Inc.
2323 Cumberland Parkway · Suite 201 · Atlanta, GA 30339

"Quality is not an act, it is a habit." -- Aristotle

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