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

[Adam J. Thornton]

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.

I'm pretty sure it works fine under FreeBSD, although I think there is only
client support for NT.

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.

Anyone have a thought on this:

The object class an object belongs to implicity defines the verbs for which
that object can be the object of the preposition "with."  That is, knives
can cut and pry.  Keys can unlock.  And so on.

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.

Adam
--
adam at princeton.edu 
"There's a border to somewhere waiting, and a tank full of time." - J. Steinman