Re: Can we solve this -- NFNF and non-1NF at Loggerheads

Dawn M. Wolthuis wrote:
>
> So, why do you write "only in the result" rather than "only in the
logical
> model"? Why do you or the computer need the logical model to include

> multiple relations with this particular set of predicates? It seems
to me
> that the DBMS software and you could both be successful with your
work with
> a model that includes only one relation, rather than three, in this
case.
> Your thoughts? Thanks. --dawn
>

The reason I write "only in the result" is that I would not want to model the PERSON table so that it has nested tables within and the reason is that it gives me more flexibility.

Suppose I want to just go over the email addresses see how many acme.com -domains there are. If this information was embedded in the PERSON-table I would have to dig it from there. I don't know what the query would look like, but it sure would be more complex than

SELECT *
  FROM EMAIL
  WHERE email_txt LIKE '%_at_acme.com'

And suppose I wanted to keep track of the spam mail the system has sent out.

I could have the table
EMAIL_LOG(emlog_id (PK), email_id (FK), time_sent, etc...)

I can reference the email simply by it's id. What if it was embedded?? I have no idea how I would refer to it!

In short, by keeping them in separate tables I keep my options open, because I don't know what needs I will have in the future.
If I embed the information I loose flexiblity.

I hope this clarifies my stand.

regards,
Lauri Pietarinen Received on Mon Feb 07 2005 - 21:22:06 CET