[klecks21]

I have a table called Enrollment which contains StdID, CourseNumber, and EnrollGrade.
StdID CourseNumber EnrollGrade
101 2201 A
101 2203 B
102 2203 C
103 2203 B
103 2201 C
103 1101 B

I need to create a trigger that will not allow a Student to enroll in CourseNumber 2205 until they have completed 2201 and 2203. I can't figure out how to go through each StdID and see if they've taken 2201 and 2203 yet.

Here's what I have so far:
Create or Replace Trigger Enroll_Rule
Before Insert on Enrollment
For Each Row
Begin
--i know i need a select statement here and then and If statement.

and now i'm totally lost. does anybody have any ideas to get me started?? Thanks a lot!

[alligatorsql.com]

Hello,

try this ..

Create or Replace Trigger Enroll_Rule
Before Insert on Enrollment
For Each Row

DECLARE

nCount PLS_INTEGER := 0;
no_course_found EXCEPTION;

Begin

SELECT COUNT(1) INTO nCount
FROM Enrollment WHERE stdid = :new.stdid
AND CourseNumber IN (2201, 2203);

IF nCount <> 2 THEN
RAISE no_course_found;
END IF;

END;

... Hope that helps ?

Best regards
Manfred Peter
(Alligator Company GmbH)
http://www.alligatorsql.com

[klecks21]

that helped me out. Thanks a lot!