From: Koon Yue Lam [mailto:kisstech@stripped]
> Hi, here is the case:
>
> one student may have more than one address, and one student
> may have more than one phone number
>
> so the db would be:
>
> student
> ----------------
> student_id
> name
> age
>
> address
> ---------------
> address_id
> student_id
> street_name
>
> phone_num
> ------------------
> student_id
> num
> extension
>
> the key of 3 tables are student_id
>
> the problems is, when I want to query both student, address
> and phone num, the sql will be
>
> select * from student s, address a, phone_num n
> where s.student_id = a.sudent_id
> and s.student_id = n.student_id
>
> it won't provide a nice result as data of student are
> repeated in every row, address and phone_num's data are
> repeated in certain rows
> The output is not suitable for reporting and may I ask what
> is the better way of design to handle the above case ?
It's good DB design, but you need to not `select *' but the specific
fields you'd like.
An example of might be:
SELECT s.name, s.age, a.street_name, n.num, n.extension
FROM students s
JOIN address a ON a.student_id = s.student_id
JOIN phone_num n ON n.student_id = s.student_id
HTH!
--
Mike Johnson Smarter Living, Inc.
Web Developer www.smartertravel.com
mike@stripped (617) 886-5539
