Re: database: prolog and relational

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Sat, 05 Jun 2004 01:07:57 +0200
Message-ID: <40c100c4$0$15375$e4fe514c@news.xs4all.nl>

Tony Douglas wrote:

> I haven't been following the thread too closely, but I could offer
> some comments which may (or probably may not) be helpful. ...

Thank you.

Long ago first I toyed with prolog on a
Sinclair ZX spectrum (48k RAM, incredible that it actually worked), and later more on a PC. Somehow I never got to do any
serious work with it. When I learned about databases I had the feeling that databases and prolog would be an excellent commercial match - but it never really happened.

So much about my intuitions :-)

> I'm pondering whether I can assert duplicate facts.
> I don't think there's anything to stop me but
> I've never intentionally done such a thing ;)

You are right:

---

Welcome to SWI-Prolog (Multi-threaded, Version 5.2.13) Copyright (c) 1990-2003 University of Amsterdam. SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome to redistribute it under certain conditions. Please visit http://www.swi-prolog.org for details.

For help, use ?- help(Topic). or ?- apropos(Word).

1 ?- assert(fact(x)).

Yes
2 ?- assert(fact(x)).

Yes
3 ?- retract(fact(A)).

A = x

Yes
4 ?- retract(fact(A)).

A = x

Yes
5 ?- retract(fact(A)).

No

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> Prolog is lots of fun, and can play some real games with what you
> think programming is (or should be) all about !
Received on Fri Jun 04 2004 - 18:07:57 CDT