The DETERMINISTIC and NOT DETERMINISTIC characteristics indicate whether a routine always produces the same result for given inputs. The default is NOT DETERMINISTIC if neither characteristic is given. To declare that a routine is deterministic, you must specify DETERMINISTIC explicitly.

The CONTAINS SQL, NO SQL, READS SQL DATA, and MODIFIES SQL DATA characteristics provide information about whether the routine reads or writes data. Either NO SQL or READS SQL DATA indicates that a routine does not change data, but you must specify one of these explicitly because the default is CONTAINS SQL if no characteristic is given.