From: pgsql-general-ow...@postgresql.org
[mailto:pgsql-general-ow...@postgresql.org] On Behalf Of Moshe Jacobson
Sent: Friday, March 28, 2014 10:31 AM
To: pgsql-general
Subject: [GENERAL] Help with exclusion constraint
Take the following table:
CREATE TABLE exclusion_example AS
(
pk_col i
On Fri, Mar 28, 2014 at 12:21 PM, Igor Neyman wrote:
> For this:
> "any given value of fk_col that there is a maximum of one row with
> bool_col = true."
>
> why don't you (instead) create partial unique index:
> CREATE UNIQUE INDEX on exclusion_example(fk_col, bool_col) WHERE bool_col
> IS TRUE;
On Fri, Mar 28, 2014 at 12:45 PM, 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
Moshe Jacobson writes:
> Take the following table:
>
> CREATE TABLE exclusion_example AS
> (
> pk_col integer primary key,
> fk_col integer not null references other_table,
> bool_col boolean not null
> );
>
> I want to ensure that for any given value of fk_col that there is a max
