A database design question.
From: Calvin Tai <calvin_tai2000_at_yahoo.com.hk>
Date: Sun, 12 May 2002 12:16:35 +0800
Message-ID: <3CDDECA3.3090505_at_yahoo.com.hk>
Dear all,
Date: Sun, 12 May 2002 12:16:35 +0800
Message-ID: <3CDDECA3.3090505_at_yahoo.com.hk>
Dear all,
I have a database design question. I got two Entities A and B. There is a relation that if something belongs to Entity A, then it must also belongs to Entity B. But if something belongs to Entity B, it MAY NOT belongs to Entity B.
The reason why i have this question because if somethings have the
nature Entity A, it should be have all the relations belongs to both
Entity A & B. While if something have the nature of entity B only,
then it only have the relations belongs to Entity B.
Is there any idea how can i define this kind of relationship in a
database design??
Best regards,
Calvin