Re: help with normalization

Let me explain a little further: this is as far as I get:

STUDENT(studentNr{PK}, Name,..., classNr{FK}) TEACHER(teachernr{PK}, name,...)

COURSE(courseNr{PK}, name,...)

CLASS(ClassNr{PK}, description

ROOM(roomNr{PK},descript,...)

ROSTER(classcode{PK}, courseNr{PK}, teacherNr{PK}, RoomNr{PK}, period{PK})

In the last table I end up with the entire thing being a composite key. I suspect it should be split,

because...how do I control:

• a class can only be in one room in one given period
• a room can only be occupied by one class in a given periuod (the same thing)
• a class can have only one course in a given period

Do I need to split this last table, and how?

thanks again, Jan

"Tonkuma" <tonkuma_at_jp.ibm.com> wrote in message news:1125667802.811424.40080_at_f14g2000cwb.googlegroups.com...
>I think that you shoud consider to add forein keys and constraints,
> before consider normalization.
> For Example:
>> - a teacher can teach several courses
>
> Add reference to StaffNo(Primary key of Teacher table) to Cource table.
>> Course(CourseNo, description, TeacherNo) (TeacherNo reference StaffNo of
>> Teacher table)
>
Received on Fri Sep 02 2005 - 15:46:49 CEST