Todo List
void add_user( int $user_id, int $class_id)
void class_name_exists( string $name)
void create_class( string $name)
void delete_class( int $class_id)
array get_classes_in_course( string $course_code)
void get_class_id( string $name)
void get_class_info( $class_id)
array get_courses( int $class_id)
array get_users( int $class_id)
void set_name( string $name, int $class_id)
void subscribe_to_course( int $class_id, string $course_code)
void unsubscribe_from_course( int $class_id, string $course_code)
Only students are unsubscribed. If a user is member of 2 classes which are both subscribed to the course, the user stays in the course.
void unsubscribe_user( int $user_id, int $class_id)
course, the user will be unsubscribed from that course
