create sequence SEQUENCE_1
start with 1
increment by 1
cache 20
nominvalue 
nomaxvalue 
nocycle
noorder

create table TEST_TRG 
( 
  a1 NUMBER not null, 
  a2 VARCHAR2(100), 
  a3 TIMESTAMP(6), 
  a4 DATE 
)

insert into test_trg values(sequence_1.nextval,'Y',null,null)

insert into test_trg values(sequence_1.nextval,'N',null,null)

insert into test_trg values(sequence_1.nextval,'N',null,null)

insert into test_trg values(sequence_1.nextval,'N',null,null)

CREATE OR REPLACE TRIGGER TEST_COMPOUND 
  FOR DELETE OR INSERT OR UPDATE ON TEST_TRG 
  COMPOUND TRIGGER 
  v_x    number; 
  v_y    number; 
 
  --Executed before DML statement  BEFORE STATEMENT IS 
  BEFORE STATEMENT IS 
  BEGIN 
    dbms_output.put_line(' '); 
    v_x := DBMS_RANDOM.random(); 
    dbms_output.put_line('BEFORE STATEMENT. X:'||v_x); 
  END BEFORE STATEMENT; 
 
  --Executed before each row change- :NEW, :OLD are available 
  BEFORE EACH ROW IS 
  BEGIN 
    v_y := DBMS_RANDOM.random(); 
    dbms_output.put('BEFORE EACH ROW. X:'||v_x); 
    dbms_output.put_line('  Y:'||v_y); 
  END BEFORE EACH ROW; 
 
  --Executed aftereach row change- :NEW, :OLD are available 
  AFTER EACH ROW IS 
  BEGIN 
    dbms_output.put('AFTER EACH ROW. X:'||v_x); 
    dbms_output.put_line('  Y:'||v_y); 
    dbms_output.put_line(' '); 
    NULL; 
  END AFTER EACH ROW; 
 
  --Executed after DML statement 
  AFTER STATEMENT IS 
  BEGIN 
    dbms_output.put('AFTER STATEMENT. X:'||v_x); 
    dbms_output.put_line('  Y:'||v_y); 
    dbms_output.put_line(' '); 
 
  END AFTER STATEMENT; 
 
END; 

MERGE INTO test_trg e 
USING (SELECT 3 as a1, 'Y' as a2 
         FROM dual 
       UNION ALL 
       SELECT 4, 'N' 
         FROM dual 
       UNION ALL 
       SELECT 6, 'N' 
         FROM dual 
       UNION ALL 
       SELECT 7, 'N' 
         FROM dual 
       UNION ALL 
       SELECT 8, 'N' 
         FROM dual) h 
ON (e.a1 = h.a1) 
WHEN MATCHED THEN 
  UPDATE SET e.a2 = h.a2 
WHEN NOT MATCHED THEN 
  INSERT 
    (a1, a2) 
  VALUES 
    (h.a1, h.a2)

  declare  
  TYPE tt is table of varchar2(1); 
  tb tt; 
  begin 
    tb := tt(); 
    tb.extend(3); 
    tb(1) := 'N'; 
    tb(2) := 'N'; 
    tb(3) := 'N'; 
    forall i in tb.first ..tb.last 
      insert into test_trg values(sequence_1.nextval,tb(i),null,null); 
  end;