Bryan
On 3/29/07, Jonathan Hedstrom <jhedstrom@xxxxxxxx> wrote:
Bryan Murphy wrote:
> Is it possible to declare a unique constraint in combination with a
> deleted flag?
>
> For example, if I have a table like this:
>
> CREATE TABLE
> (
> ID NOT NULL PRIMARY KEY,
> Key VARCHAR(32) NOT NULL,
> Value VARCHAR(32) NOT NULL,
> Deleted INT NOT NULL DEFAULT 0
> );
>
> can I declare a unique constraint that only checks Key and Value when
> Deleted = 0?
Yes, something like this:
CREATE UNIQUE INDEX index_name ON table_name ( unique_field) WHERE
deleted=0;
-Jonathan
