Re: Constraints or assertions
Date: Wed, 6 May 2009 06:24:48 -0700 (PDT)
A quick comment, SQL-92 allows CHECK() constraints to have any valid search condition, evern those that referencs other tables or its own table at aggregate levels. But all CHECK() constraints are TRUE for an empty table.
The reason we defined the CREATE ASSERTION was that it is at the schema level and it works with empty tables. This is why CHECK() constraint names are global to the schema. Received on Wed May 06 2009 - 15:24:48 CEST