[DGD] Need some guidance

[Erwin Harte]

On Fri, Feb 01, 2002 at 10:39:17PM +0000, Shevek wrote:
> What I'm looking to do is to hook a DGD server up to a MySQL database. 
> Sounds a bit odd, but I want to use something like Apache to serve web 
> pages with info off the database, PHP to run the dynamic content, and the 
> DGD server to process activity within the site (ie Playing around with the 
> information without being driven by user events), and provide chat via a 
> Java applet (Probably just a simple binary connection).
> 
> Ever so minor problem (:>) is that I can't figure out how to access the 
> database from within DGD. The  rest doesn't appear incredibly difficult to 
> put together, but it all revolves around that hookup.

You'd have to either link the MySQL libraries into DGD with some
special commands to execute queries (which sounds like an interesting
challenge, to me), or have some ability to create outgoing connections
and connect to the MySQL port.  No clue how easy it is to communicate
with a MySQL daemon, though.

> Any suggestions on how to proceed would be gratefully received. Or, and it 
> sounds wierd now I think of it, would it be better to just lose the MySQL 
> functionality and code some DB style object directly in LPC (Sounds 
> difficult to do well for multiple connections, or for neatness of DB).

It all depends on what you want to do.  If you keep an object per
table for the indexes (make sure you don't trip over the mapping or
array size limitations) and an object per X table entries, then you
can probably do some fairly efficient queries without needing to swap
things in unnecessarily.  How many entries you store per object all
depends on how big you think the individual entries will be (if you
have some text or blob columns then it can add up rather quickly).

Next problem: How to figure out where to store a table row.  You
probably want to do something based on an md5 hash of the primary
index of that row, take the first X bytes/characters (depending on
whether you handle it as hex or not) and use that in a mapping from
md5-indices to objects.

Just my bit of brainstorming, hope it gets you started in the right
direction somehow. :-)

Erwin.
-- 
Erwin Harte <harte at xs4all.nl>
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