newbie question: prolog's interface,relation database's sql relationship

From: chenyu (chenyu468_at_yahoo.com)
Date: 01/19/04 

Date: 18 Jan 2004 17:21:01 -0800

Hello everyone,
I am learning prolog now. But there is a question in my mind. What's
the relationship between prolog's logic interface and relation
database's sql search function.

1. prolog's logic interface is based on first-order logic. It requires
that the rules and facts are stored in memory. <== always in memory?

2. prolog's inference's key operation is "unify" operation (between
uninstantiated variable and atomic,struct, instantiated variable).
Therefore it is sequence operation and can't change to parallel
operation.<===can't or mostly can't or mostly can?

3. relation database sql query function is based on the "relation
algebra". It can be easily done by paralleled.

4. relation database sql query doesn't require all data are stored in
the memory. It just requires that the data are under management of
DBMS.

5. If prolog's facts or rules are stored in the relation database. It
is not helpful for prolog's inference speed. Because it is sequence
operation and use data one record by another. <=== Is it right?

6. Therefore, prolog's facts and rules are always stored in the files,
not in relation db.

Thank you for your attention.
kind regards/chenyu