CREATE OR REPLACE TRIGGER TRIGGER 1
AFTER INSERT OR UPDATE OF OFFERING
FOR EACH ROW
BEGIN
IF (select OFFERINGID from OFFERING where to_char(STARTDATE, 'Mon') = 'DEC')
AND 
IF (SELECT COURSEID FROM COURSE where DURATION = 5)
THEN
RAISE_APPLICATION_ERROR(
-20001,'Cannot run 5 day course in December');
END IF
END;

 create trigger STUDENT_EVAL
  before insert on STUDENTOFFERING
  for each row when (new.evaluation = 0)
begin
  insert into STUDENT_AUDIT (SNAME, COURSEID, ATTENDATE, INSTRUCTORID, EVALUATION)
  select :new.NAME, :new.COURSEID, O.SDATE, O.INSTRUCTOR, :new.EVAL
  from   OFFERING O
  where  :new.OFFID = O.OFFID;
end;

CREATE OR REPLACE TRIGGER TRIGGER1
AFTER INSERT OR UPDATE ON OFFERING
FOR EACH ROW
BEGIN
IF (select OFFERINGID from OFFERING where to_char(STARTDATE, 'Mon') = 'DEC')
AND 
IF (SELECT COURSEID FROM COURSE where DURATION = 5)
SELECT C.COURSEID, TITLE FROM COURSE C
WHERE :NEW.COURSEID = C.COURSEID
THEN
RAISE_APPLICATION_ERROR(
-20001,'Cannot run 5 day course in December');
END IF
END;

  l_offeringid offering.offeringid%type;
BEGIN
  SELECT offeringid INTO l_offeringid
    FROM offering
    WHERE ...

  IF l_offeringid = 1234 THEN
     do_something;
  END IF;
 
  ...

CREATE OR REPLACE TRIGGER TRIGGER1
AFTER INSERT OR UPDATE OF STARTDATE ON OFFERING
FOR EACH ROW
BEGIN
SELECT C.COURSEID, C.TITLE, O.OFFERINGID, O.STARTDATE, C.DURATION FROM COURSE C, OFFERING O
WHERE :NEW.COURSEID = C.COURSEID

IF (select OFFERINGID from OFFERING where to_char(STARTDATE, 'Mon') = 'Dec')
AND 
IF (SELECT COURSEID FROM COURSE where DURATION = 5)
THEN
RAISE_APPLICATION_ERROR(
-20001,'Cannot run 5 day course in December');
END IF
END;

INSERT INTO OFFERING VALUES
('11', '3', '01-DEC-2008', 'PRAGUE', '2')

create or replace trigger COURSE_DURATION
BEFORE insert on offering
for each row
begin
  select *
  from   course c
  where  c.courseid = :new.courseid
  and    to_char(startdate, 'Mon') = 'Dec'
  and    c.duration = 5;
RAISE_APPLICATION_ERROR
(-20001,'Cannot run 5 day course in December')
end;

create or replace trigger COURSE_DURATION
before insert on offering
for each row When (to_char(new.startdate, 'Mon') = 'Dec')
declare
  december exception; 
pragma exception_init(december, -20001);
dummy number;
begin 
select 1 into dummy from course c where c.courseid = :new.courseid 
and duration = 5;
  raise december;
exception
  when no_data_found then
    null;
end;

('20', '2', '02-DEC-2008', 'OSLO', '2')
    *

ERROR at line 2: 
ORA-20001: 
ORA-06512: at "OPS$0466065.COURSE_DURATION", line 5 
ORA-04088: error during execution of trigger 'OPS$0466065.COURSE_DURATION' 

INSERT INTO OFFERING VALUES
('20', '2', '02-DEC-2008', 'OSLO', '2')

create trigger STUDENT_EVAL
  before insert on STUDENToffering
  for each row when (new.evaluation = 0)
begin
  insert into STUDENTAUDIT(sname, courseid, dateofattendance, instructorid, evaluation)
  select s.sNAME, c.COURSEID, O.StartDATE, O.INSTRUCTORid, :new.EVALuation
  from   OFFERING O, student s, course c 
  where  :new.OFFeringID = O.OFFeringID and :new.studid = s.studid and o.courseid = c.courseid;
end;

insert into studentoffering values
('05', '10', 0, 'A')

raise december;