Search Postgresql Archives

Weird unique constraint

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



I have the following constraint which almost works:

ALTER TABLE ingredientforms ADD CONSTRAINT
ingredientforms_UniqueIngredientForm UNIQUE(IngredientId,
FormDisplayName);

However, I want to allow rows that have the same IngredientId
FormDisplayName /iff/ FormDisplayName is null.  If FormDisplayName is
not null, then it must be unique.

1, NULL
1, NULL

Would be allowed.

1, 'Foo'
1, 'Foo'

would violate the constraint.

1, 'Foo'
1, 'Bar'

would be allowed.

Any way to do this?  Insert performance is not an issue since the
table is almost never changed..

Mike

-- 
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Postgresql Jobs]     [Postgresql Admin]     [Postgresql Performance]     [Linux Clusters]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Postgresql & PHP]     [Yosemite]
  Powered by Linux