WHENEVER SQLERROR CONTINUE
create table mhe_test( id number not null
                     , name varchar2(50)
                     , hours_worked number
                     )
/

CREATE TRIGGER BRI_MHE
AFTER  INSERT  ON MHE_TEST
FOR EACH ROW
Declare
  Cursor c_total_hours
      is
  Select sum(hours_worked)
    From mhe_test
   WHERE name = :new.name;

  v_total number;

Begin
  Open c_total_hours;
  Fetch c_total_hours Into v_total;
  Close c_total_hours;

  -- do some processing
  If v_total > 50 Then
    Null;
  End if;
End;

/

Insert into mhe_test values(1,'MHE1',3);
Insert into mhe_test values(2,'MHE2',7);
                     
Drop table mhe_test
/