Constraints can be added, modified, or removed using:
Through SQL, a constraint can be added to the column of a table using the CREATE TABLE statement. If the table already exists, then the ALTER TABLE statement can be used to add the constraint. The ALTER TABLE statement can also be used to DROP the constraint.
Using CL commands, the Add PF Constraint (ADDPFCST) command can be used to add or change a constraint, and the Remove PF Constraint (RMVPFCST) command can be used to remove a constraint.
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