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

A searchCondition is any boolean expression that meets the requirements specified in .

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