erd to db

From: Yves Guerin <yves.guerin_at_muhc.mcgill.ca>
Date: Thu, 21 Mar 2002 18:21:59 GMT
Message-ID: <bxpm8.7127$R8.88795_at_carnaval.risq.qc.ca>

Hello,

I have question about to map a erd to a ralational database:

I have the following entities: E and W in binary ERD

E: owner of W
W: weak
E: primary key is e1
W: primary key is w1

The relationship between E and W is R and R has a primary key: r1 So to map my weak entity W do I map this as:

1-

    W primary key will be: pk of E + pk of R + pk of W     E: add pk of R as fk

OR

2-

    W primary key will be: pk of R + pk of W     E: add pk of R as fk

OR

3-

    W primary key will be: pk of E + pk of R + pk of W

Thank you

Yves

--
Yves Guerin
CUSM-MUHC
Groupe Interfaces
Montreal - Canada

Received on Thu Mar 21 2002 - 19:21:59 CET