tableLevelConstraint

[ CONSTRAINT constraintName ]
{
    CHECK ( searchCondition ) |
    {
        PRIMARY KEY ( simpleColumnName [ , simpleColumnName ]* ) |
        UNIQUE ( simpleColumnName [ , simpleColumnName ]* ) |
        FOREIGN KEY ( simpleColumnName [ , simpleColumnName ]* )
            REFERENCES clause
    }
}

A searchCondition is any boolean expression that meets the requirements specified in Requirements for search conditions.

If a constraintName is not specified, Derby generates a unique constraint name.

Related reference
columnLevelConstraint
REFERENCES clause