CREATE TABLE tb_updates (UPD_ID Varchar(50), UPD_APP Varchar(250), UPD_VERSION Integer DEFAULT 0, UPD_IMAGE Blob, UPD_TIMESTAMP DATE)

CREATE TRIGGER  IF NOT EXISTS tr_tb_updates_bi 
         BEFORE INSERT ON tb_updates
         FOR EACH ROW BEGIN
         INSERT INTO tb_updates (upd_id) VALALUES (UPPER(hex(randomblob(16))));
         END

insert into tb_updates (upd_app) values ('ttt')

CREATE OR REPLACE TRIGGER tr_tb_payments_bi
 BEFORE
  INSERT
 ON tb_payments
REFERENCING NEW AS NEW OLD AS OLD
 FOR EACH ROW
BEGIN
  IF :NEW.pay_id IS NULL
  THEN
    SELECT SYS_GUID
      INTO :NEW.pay_id
      FROM DUAL;
  END IF;
END;