CHECK constraint controls the values in the associated column. In other words,
CHECK constraints ensures that the value in a certain column satisfy a Boolean expression or not.
CHECKconstraint on the "Age" column when the "tblCustomer" table is created. The
CHECKconstraint ensures that the customer's age greater or equal to 18 years:
CHECKconstraint on the "Age" column when table already exists into the database:
CHECKconstraint "UC_Customer" from "tblCustomer" table: