Model a Check Constraint
A Check Constraint enforces domain integrity by limiting the values that are accepted by a database Table column.
Access Tools | Database Builder | Click on Table name > Constraints | Right-click | Add New Constraint (Ctrl+N)
A new constraint is added to the Constraints tab, with the default type index. Click on the drop-down arrow and select check. See the Help topic Check Constraints for information on defining the new constraint.
To delete a check constraint you no longer require, right-click on the constraint name on the Constraints tab and select the Delete constraint <name> option. The constraint is immediately removed.