How to: Modify Check Constraints (Visual Database Tools)
Modify a check constraint when you want to change the constraint expression or the options that enable or disable the constraint for specific conditions. For information about how to define the correct syntax for a constraint, see How to: Define Check Constraint Expressions (Visual Database Tools).
To modify a check constraint
In your database diagram, right-click the table containing the constraint, then select Properties from the shortcut menu.
Open the Table Designer for the table containing the constraint, right-click in the Table Designer, and choose Check Constraints from the shortcut menu.
Choose the Check Constraints tab.
Select the constraint you want to change from the Selected Check Constraint list.
Complete an action from the following table:
Some databases have different functionality for check constraints.
Follow these steps
Edit the constraint expression
Type the new expression in the Expression field.
Rename the constraint
Type a new name in the Name field.
Apply the constraint to existing data
Select the Check Existing Data on Creation or Enabling option.
Disable the constraint when new data is added to the table or when existing data is updated in the table.
Clear the Enforce Constraint for INSERTs and UPDATEs option.
Disable the constraint when a replication agent inserts or updates data in your table. For more information, see Controlling Constraints, Identities, and Triggers with NOT FOR REPLICATION.
Clear the Enforce For Replication option.
The constraint is updated in the database when you save your table or diagram.