Developers delete a check constraint when they want to remove the limitations on data values that are accepted in the column or columns included in the constraint expression. When Developers working with SQL Server “Denali”, MS SQL Server 2008 R2 and MS SQL Server 2005 want to delete a check constraint, they should follow the next steps:
1. In Object Explorer, right-click the table with the check constraint, and click Design (Modify in SP1 or earlier). The table opens in Table Designer.
2. From the Table Designer menu, click Check Constraints.
3. In the Check Constraints dialog box, select the constraint in the Selected Check Constraint list.
4. Click the Delete button.
The constraint is deleted from the database when they save the table.