CREATE OR REPLACE TRIGGER "DNRS2"."TRG_BI_TBL_DOMAIN_PERFORMANCE"
BEFORE INSERT
ON tbl_domain_performance
FOR EACH ROW
DECLARE
last_Sequence NUMBER;
last_InsertID NUMBER;
BEGIN
IF (:NEW.id IS NULL) THEN
SELECT seq_tbl_domain_performance.NEXTVAL INTO :NEW.id FROM DUAL;
ELSE
SELECT NVL(Last_Number, 0) INTO last_Sequence
FROM User_Sequences
WHERE UPPER(Sequence_Name) = UPPER('seq_tbl_domain_performance');
SELECT :NEW.id INTO last_InsertID FROM DUAL;
WHILE (last_InsertID > last_Sequence) LOOP
SELECT seq_tbl_domain_performance.NEXTVAL INTO last_Sequence FROM DUAL;
END LOOP;
END IF;
END;

CREATE SEQUENCE "SEQ_TBL_DOMAIN_PERFORMANCE" MINVALUE 1 MAXVALUE 9999999999999999999999999999;


caused:
Error(23,1): PLS-00103: Encountered the symbol "CREATE"

Are these CREATE statements part of the same file?

If so, first create a sequence. Then create a trigger and put a slash (/) sign to terminate it. . Something like

hmm... i did a mistake by combining trigger and sequence together ><!!! haha.. anyway thx for your reply.