Adding check constraints - IBM DB2 9.7 for Linux, UNIX, and Windows

You can add check constraints to your table or nickname. A check constraint sets restrictions on data added to the table or nickname. Check constraints are enforced when rows in the table or nickname are inserted or updated. You can define a check constraint that references a single column.

Before you begin

To add check constraints, you must have at least one of the following privileges on the table to be altered:

ALTER privilege
CONTROL privilege
DBADM authority
ALTERIN privilege on the schema of the table

Procedure

To add check constraints using the Control Center:
1. Open the Alter Table notebook if you are adding a unique key to a table: From the Control Center, expand the object tree until you find the Tables folder. Click the Tables folder. Any existing tables are displayed in the pane on the right side of the window. Right-click the table you want in the contents pane and select Alter from the pop-up menu. The Alter Table notebook opens. If you are adding check constraints on a nickname, open the Alter Nickname notebook.
2. On the Check Constraints page, click Add. The Add Check Constraint window opens.
3. For as many check constraints as you are adding: Specify the check condition for the constraint that you are defining, type a name for the check constraint, and optionally type a comment to document the new check constraint.
To add a check constraint using the command line, use the ALTER TABLE statement.