Create a trigger - sql

Question

Create a trigger called NewEntry, that will not allow a result to be inserted into the student exam table if it is less than zero. In your query display a suitable message if the result is less than zero and supply code to test the trigger.
This is what I have done, but I keep getting
warning : trrigger created with compilation errors.
This is my code, please help!
CREATE OR REPLACE TRIGGER NewEntry
AFTER INSERT OR UPDATE ON Assignment2.Student_Exam
FOR EACH ROW
DECLARE
Results NUMBER;
BEGIN
IF(:NEW.Results < '0')
THEN
RAISE_APPLICATION_ERROR
(-20700,'Student's result cannot be less-than ZERO..Enter valid Results':);
ENDIF;
END;
/

Answer 1

END IF, not ENDIF. Also as Jeremy C mentions above you need to create the trigger as BEFORE INSERT OR UPDATE

Answer 2

you listen the other answers but one more thing ,
you must focus on :NEW.Results this is the thing.

Answer 3

There are two errors: Firstly it is 'END IF' not ENDIF, secondly you have apostrophe's in your message.
The correct code is:
CREATE OR REPLACE TRIGGER NewEntry
AFTER INSERT OR UPDATE ON Assignment2.Student_Exam
FOR EACH ROW
DECLARE
Results NUMBER;
BEGIN
IF(:NEW.Results < '0')
THEN
RAISE_APPLICATION_ERROR
(-20700, 'students result cannot be less-than ZERO..Enter valid Results:');
END IF;
END;
/
As others have said you could have de-bugged this yourself by typing show errors; This would have given you the answer e.g.
SQL> show errors;
Errors for TRIGGER NEWENTRY:
LINE/COL ERROR
-------------------------------------------------------------------------
7/18 PLS-00103: Encountered the symbol "S" when expecting one of the
following:
) , * & = - + < / > at in is mod remainder not rem =>
<an exponent (**)> <> or != or ~= >= <= <> and or like like2
like4 likec between || multiset member submultiset
edit: In reply to Ersin - If it was New.Results then you would get a bind error e.g.
SQL> show errors;
Errors for TRIGGER NEWENTRY:
LINE/COL ERROR
-------- -----------------------------------------------------------------
4/4 PLS-00049: bad bind variable 'NEW.RESULTS'
SQL>
This will be a result of 'RESULTS' not being a column in Student_Exam, which I presume does exist given the rest of the statement.