[MUD-Dev] Re: DBMS in MU*'s

[Jeroen Ruigrok/Asmodai]

At 19:37 19-07-98 , you wrote:
>On Sun, Jul 19, 1998 at 05:46:53PM +0200, Jeroen Ruigrok/Asmodai wrote:
>> At 17:25 19-07-98 , you wrote:
>> Freeware SQL Daemons/servers out there for FreeBSD or Windows NT?
>
>PostgreSQL is free.  Or was last I checked about two months ago.

Reading <http://www.postgresql.org> as I type this =)

>It claims to be an ORDBMS, which basically means you can define tables that
>inherit their structure from other tables.  Which works well enough for an
>object model, although I'm having a problem defining direct objects on it.

A ORDBMS would be better than either a OO- or R-DBMS alone in my humble
revised opinion as objects (or items and such) are related to a person or
location, but can be children of one parent. Imagine a inn where all knives
were created by hand instead of creating childs from a parent.

>How do I implement an object model that specifies what objects provide
>direct objects for various verbs?  There isn't a one-to-one mapping between
>classes as defined above and direct-object-classes.  For example, say we
>have a class liquid_container; now both a wineskin and a crystal goblet are
>liquid_containers.  But one provides a direct object to "break" and one
>does not. 
>
>Multiple inheritance may provide a solution.  That is, I create an empty
>table (class) "fragile" and nestle it under "object".  Then the goblet
>inherits both "liquid_container" and "fragile".  And if someone tries to
>break it, we look to see if it's a member of "fragile" (or "fragile*" if I
>have subclassed "fragile" in the meantime).
>
>I'm worried that this will cause a huge explosion in the number of tables,
>though.  Plus an awful lot of ugly special case code in the server.

I understand yer concern, but is a 'condition' table (or something like
that) which lists the states an object can be in not the solution then? I
mean, create a table with entries like:

rock, glass, velvet, wood and paper and assign values about the subject
being able to break, torn apart etc...

This would eliminate multiple tables and generally provide a good addition
to the MU*.

HTH,

--
Jeroen Ruigrok van der Werven / Asmodai <asmodai(at)wxs.nl>
ICQ-UIN: 1564317 .:. Ninth Circle Enterprises
Network/Security Specialist

As far as ye can't tell, I am the Future in Computer Hell...