CREATE OR REPLACE TRIGGER PutOnWaitingList
    INSTEAD OF INSERT ON CourseEnrollmentInsert
    FOR EACH ROW
    DECLARE
        studentCount INTEGER;
        courseCapacity INTEGER;
    BEGIN
        SELECT COUNT (*) INTO studentCount
        FROM   CourseEnrollmentInsert CEI
        WHERE  CEI.course = :NEW.course;

        SELECT numStudents INTO courseCapacity
        FROM   CourseEnrollmentInsert CEI
        WHERE  CEI.course = :NEW.course
               AND ROWNUM = 1;
        INSERT INTO Log (text, TIME) VALUES ('Before if values: ' || TO_CHAR(studentCount) || ' and ' || TO_CHAR(courseCapacity), SYSTIMESTAMP);
        -- XXX Above
        IF  studentCount >= courseCapacity THEN
            INSERT INTO WaitingFor(course, student, since) VALUES
                (:NEW.course, :NEW.student, SYSTIMESTAMP);
            INSERT INTO Log (text, TIME) VALUES ('Course full', SYSTIMESTAMP);
        ELSE
            INSERT INTO CourseEnrollment(course, student) VALUES
                (:NEW.course, :NEW.student);
            INSERT INTO Log (text, TIME) VALUES ('Course not full', SYSTIMESTAMP);
        END IF;
    END PutOnWaitingList;