Felix Kater <fkater@xxxxxxxxxxxxxx> writes: > On Tue, 8 May 2007 15:54:08 +0200 > Martijn van Oosterhout <kleptog@xxxxxxxxx> wrote: >> A unique index is not a "substitute" for a unique constraint, they're >> exactly the same thing. > Yes. For this reason I didn't have to implement *both* 'unique > constraints' *and* 'unique indices' in my pg interface. If you are trying to get away with a dumbed-down subset of SQL, be prepared for people to refuse to use your tool ;-). You have to support the unique-constraint syntax because the SQL spec says so (and people are used to it), and you have to support the create-index syntax because it gives access to functionality not available through the constraint syntax. Unique indexes on expressions for instance. regards, tom lane
