trigger get next value using sequence object.sql

CREATE SEQUENCE MYLIB.MYAUTO_INCREMENTING_SEQ
AS BIGINT
START WITH 1
INCREMENT BY 1
NO ORDER
NO CYCLE
NO MINVALUE
NO MAXVALUE
CACHE 20;

CREATE OR REPLACE TRIGGER FILESRDB.TESTDDS_MAINTAIN
BEFORE INSERT ON FILESRDB.TESTDDS
  REFERENCING NEW AS N FOR EACH ROW
  BEGIN ATOMIC
    SET n.tstid = NEXT VALUE FOR MYLIB.MYAUTO_INCREMENTING_SE;
  END

trigger get next value.sql

CREATE OR REPLACE TRIGGER FILESRDB.TESTDDS_MAINTAIN
BEFORE INSERT ON FILESRDB.TESTDDS
  REFERENCING NEW AS N FOR EACH ROW
  BEGIN ATOMIC
    DECLARE V_NEXT_ID CHAR(8) DEFAULT '';
    DECLARE CURSOR_NEXT_ID CURSOR FOR
        SELECT COALESCE(MAX(tstid), 0) + 1 FROM FILESRDB.TESTDDS;
        
    OPEN CURSOR_NEXT_ID ;
    FETCH CURSOR_NEXT_ID INTO V_NEXT_ID;
    SET n.tstid = V_NEXT_ID;
    CLOSE CURSOR_NEXT_ID;
  END