Performance and CHECK constraints

I read somewhere that on a VIEW that references multiple tables (via a UNION) a CHECK CONSTRAINT can speed access in certain cases. For example, if the VIEW joins several tables that have monthly data (say for the last 12 months) and each table has a CHECK CONSTRAINT that limits the data to a specific month, then any query against that VIEW refereencing the date will not attempt to search any of the the tables behind the VIEW that the CHECK CONSTRAINT says can't be in that table. In other words Oracle looks at the CHECK CONSTRAINT and determines that looking in a particular table is not needed because of the constraint. Oracle in this case doesn't even look in the indexes, it just skips that table.

Is this a true statement?

Any help is appreciated. Received on Wed Sep 22 1999 - 14:22:49 CDT