check age trigger from two separate tables in oracle sql - sql

Question

I need to create a trigger that checks that the age (in years) of the participant is higher than the minimum age of the race he/ she participates in. To do this I need to get information from the participants table and the race table. I need to add this trigger to the results table
here are my tables:
CREATE TABLE race
(
RaceID int,
Location varchar2 (60),
StartDate Date,
RaceTime Date,
MinAge int,
);
CREATE TABLE participant
(
ParticipantID int,
"Name" varchar2 (60),
DateOfBirth date,
Sex varchar2 (1),
Age int
);
CREATE TABLE results
(
RaceID int not null unique,
ParticipantID int not null unique,
position number (2)
);
here is what I have created so far:
create or replace TRIGGER dob_trg
BEFORE INSERT OR UPDATE ON RESULTS
FOR EACH ROW
DECLARE
RACE_MINAGE NUMBER;
PARTICIPANT_AGE NUMBER;
BEGIN
SELECT RACE.MINAGE, PARTICIPANT.AGE
INTO RACE_MINAGE, PARTICIPANT_AGE
FROM RACE PARTICIPANT
WHERE RACE.RACEID = :NEW.RACEID;
IF : NEW.AGE < : NEW.MINAGE THEN
RAISE_APPLICATION_ERROR(-20000, 'Participant too young!');
END IF;
enddob_trg;
However I'm getting the following error
Error(9,6): PLS-00103: Encountered the symbol ":"
Any help greatly appreciated!

Answer 1

Erros :
Table race - there is an extra comma at the end of you MinAge col
CREATE TABLE race
(
RaceID int,
Location varchar2 (60),
StartDate Date,
RaceTime Date,
MinAge int,
);
Inside trigger errors:
IF : NEW.AGE < : NEW.MINAGE THEN should be
IF :NEW.AGE < :NEW.MINAGE THEN
Your create trigger is on table RESULTS but the action is made on a column called AGE that belongs to the participant table .
Fix this logic before going forward.
One more error inside your trigger :
FROM RACE PARTICIPANT
add a comma between tables
Fixed trigger
-here i what i think your trigger should look like !
Compile it and give it a try
See my logic :
This query will store the values of minage using the predicate "NEW.ParticipantID"
SELECT RACE.MINAGE, PARTICIPANT.AGE
INTO RACE_MINAGE, PARTICIPANT_AGE
FROM RACE, PARTICIPANT
WHERE RACE.RACEID = :NEW.ParticipantID;
This part :- if the RACE_MINAGE is bigger or equal then
IF :NEW.AGE <= RACE_MINAGE THEN
RAISE_APPLICATION_ERROR(-20000, 'Participant too young!');
END IF;
Complete trigger
CREATE OR REPLACE TRIGGER dob_trg
BEFORE INSERT OR UPDATE ON participant
FOR EACH ROW
DECLARE
RACE_MINAGE NUMBER;
PARTICIPANT_AGE NUMBER;
BEGIN
SELECT RACE.MINAGE, PARTICIPANT.AGE
INTO RACE_MINAGE, PARTICIPANT_AGE
FROM RACE, PARTICIPANT
WHERE RACE.RACEID = :NEW.ParticipantID;
exception
when NO_DATA_FOUND then
NULL; -- or do something else you choose
IF :NEW.AGE <= RACE_MINAGE THEN
RAISE_APPLICATION_ERROR(-20000, 'Participant too young!');
END IF;
end;

Answer 2

IF : NEW.AGE < : NEW.MINAGE THEN
You should remove the whitespace after the : symbol.
IF :NEW.AGE < :NEW.MINAGE THEN
Also, it looks like you're missing a comma in your FROM clause:
FROM RACE PARTICIPANT
But that wouldn't make your code work yet, because you're testing the wrong fields in your IF statement. Also, you're not filtering the participantId.