Check constraints
Check constraints specify a condition or requirement on a data value before data can be assigned to a column during an INSERT or UPDATE statement. If a row evaluates to false for any of the check constraints that are defined on a table during an insert or update, the database server returns an error. However, the database server does not report an error or reject the record when the check constraint evaluates to NULL. For this reason, you might want to use both a check constraint and a NOT NULL constraint when you create a table.
Customer_Number >= 50000 AND Customer_Number <= 99999
vce_num MATCHES '[2-9][2-9][0-9]-[0-9][0-9][0-9][0-9]'
For additional information about check constraints, see the CREATE TABLE and ALTER TABLE statements in the HCL OneDB™ Guide to SQL: Syntax.