Click here to view and discuss this page in DocCommentXchange. In the future, you will be sent there automatically.

SQL Anywhere 10.0.1 » SQL Anywhere Server - SQL Usage » Ensuring Data Integrity » Using table and column constraints

Working with table and column constraints in Sybase Central Next Page

Altering and dropping CHECK constraints

There are several ways to alter the existing set of CHECK constraints on a table.

Sybase Central lets you add, alter and drop both table and column CHECK constraints. For more information, see Working with table and column constraints in Sybase Central.

Dropping a column from a table does not drop CHECK constraints associated with the column held in the table constraint. Not removing the constraints produces a column not found error message upon any attempt to insert, or even just query, data in the table.


Table CHECK constraints fail if a value of FALSE is returned. If the condition returns a value of UNKNOWN the behavior is as though it returned TRUE, and the value is allowed.