Online Documentation for SQL Administrator for SQL Server
Check Constraint Editor
A Check specifies an expression producing a Boolean result which new or updated rows must satisfy for an insert or update operation to succeed. Expressions evaluating to TRUE or UNKNOWN succeed. Should any row of an insert or update operation produce a FALSE result an error exception is raised and the insert or update does not alter the database. A check constraint specified as a column constraint should reference that column's value only, while an expression appearing in a table constraint may reference multiple columns.
To open a check constraint in Check Constraint Editor, double-click it in the Checks list, or use the Edit Check Constraint... item of the context menu within the Check constraints tab of Table Editor.
