Re: class design vs. db design

From:

"Oliver Wong" <owong@castortech.com>

Newsgroups:

comp.lang.java.programmer

Date:

Tue, 19 Dec 2006 13:46:04 -0500

Message-ID:

<MrWhh.91161$_n2.574853@weber.videotron.net>

"John_Woo" <john_woo@canada.com> wrote in message
news:1166531523.393419.207410@79g2000cws.googlegroups.com...

Hi,

if I want to reflect a 1:1 relationship for user:account, the design
model may be:

for class:
A. User
   -------------
  int user_id;
int account_id;

B. User
    ------------
   int user_id;
   Account account;

for db:
C. User (user_id int); Account(account_id int, user_id int)

D. User (user_id int, account_id int); Account (account_id int)

Questions:
1. How to compare A vs. B in terms of OO design, JDO (java data object)

I like B better. It looks like less work to get the account from the
user.

2. How to compare A vs. B in terms of db schema (with foreign key
constraint)

I suppose A would be slightly less work to implement a ORM for, but you
could just download an ORM like Hibernate to do the work for you, so I'd
still stick with B.

3. C vs. D, which is better? should create user first or account first?

If the relation is 1:1, why not stick it all in one big table?

- Oliver