Re: Re: how to implement a foreign key type constraint against a not unique column - Mailing list pgsql-general

From Alban Hertroys
Subject Re: Re: how to implement a foreign key type constraint against a not unique column
Date
Msg-id 51DA7A20-4D7B-4351-AD01-C48A322BBE8C@solfertje.student.utwente.nl
Whole thread Raw
In response to Re: how to implement a foreign key type constraint against a not unique column  (Jasen Betts <jasen@xnet.co.nz>)
List pgsql-general
On Jan 25, 2009, at 3:07 AM, Jasen Betts wrote:

>> I want to use this column as a foreign key on a column in another
>> table
>> (column 2), but cannot without a full unique index.
>
> a full unique index is easy use an expression that's null for -1.
>
> create unique index foobar on foo( ( case fee when -1 then null else
> fee end ) );


anything wrong with create unique index foobar on foo where fee <> -1 ?

Alban Hertroys

--
If you can't see the forest for the trees,
cut the trees and you'll see there is no forest.


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