[DGD] DGD & MySQL

[bart at wotf.org]

I never looked at embedding sqlite or an sql database client, but I did look
at creating a tdbm or berkeleydb extension for DGD, and atomic functions and
transactions are where things become rather non trivial indeed :)

To get this right, you'd want DGD to treat database objects as internal
variables so they can be taken into consideration for a commit/rollback. On
the LPC level this should work similar to a map tied to a dbm in perl (opendbm).

The alternative is getting your extension involved in deciding on doing a
commit/rollback.

Either solution means cutting deep into the internals of DGD in a way that is
bound to make tracking the development version of DGD difficult, and will
likely need a complete rewrite for DGD/MP.

I think technically it is feasable, but considering the amount of work it
takes, I haven't proven enough of a need for it to myself to go on with it.

As for having to store your lpc objects in such a database. that depends on
what you want your database for.

One of the initial reasons for me to look at some form of database extension
is to be able to store very large key:value sets (for example for dictionary
lookups for a natural language parser or spell checker), not something for
storing lpc object state.

Thinking of what I'd do with an SQL database.. probably store data for a
'galaxy scale' economy for my game :)

At any rate, such an extension would have some advantages over all other ways
to accomplish this.

Atomic functions and transactions can be integrated flawlessly

It can get an answer to a request in the same execution round (provided your
database can provide an answer to a query in a reasonable amount of time or
you will stall your mud). SQL removes much of this advantage because many
things for which this matters can and usually are solved in SQL and handled by
the database server, but it will still make writing LPC code that talks to
your SQL server a bit easier.

That said, an external daemon as Par suggests allows you to use a language
more suitable for talking to an sql database, and is technically a lot easier
to get right. Its also a proven solution :)

Bart.

On Thu, 18 Sep 2008 09:35:02 -0700 (PDT), Noah Gibbs wrote
> Sure, but that'll still take most of the same effort.  The hard 
> part is integrating DGD features like atomic functions with SQL 
> features like transactions, as well as more fundamental stuff like 
> storing all your DGD objects in some kind of SQL format.
> 
> --- On Thu, 9/18/08, Kurt Nordstrom <kurt at blar.net> wrote:
> 
> > From: Kurt Nordstrom <kurt at blar.net>
> > Subject: Re: [DGD] DGD & MySQL
> > To: "All about Dworkin's Game Driver" <dgd at dworkin.nl>
> > Date: Thursday, September 18, 2008, 8:44 AM
> > Embedding SQLite might be another viable alternative to
> > MySQL too.
> > 
> > http://www.sqlite.org/
> > 
> > As they claim, self-contained, serverless and config-free.
> > 
> > -Kurt
> > 
> > > On 9/18/08 7:23 AM, Per Newberg wrote:
> > >> Greetings all!
> > >>
> > >> This is the first time I write here.. so hi! :-)
> > >>
> > >> My question is regarding DGD & SQL...
> > >>
> > >> Have anyone tried doing anything like this? Making
> > [My]SQL queries
> > >> from within DGD & LPC code?
> > >
> > > Unless you're really hungry to drop hundreds of
> > hours of work into this,
> > > my recommendation would be to design a new minimal
> > application-specific
> > > protocol that does precisely what you want and nothing
> > else and contains
> > > no SQL or table names, just your own logical
> > operations and references.
> > >
> > > You write a DGD client for the protocol and you write
> > a small Java
> > > server for it. The Java server takes requests from DGD
> > (localhost
> > > connection) and translates them into SQL through JDBC,
> > and mutates the
> > > results for DGD.
> > >
> > > This way you get a storage-agnostic interface (maybe
> > you'd want to
> > > switch to Berkeley DB at some point, for example) and
> > you don't have to
> > > deal with actual database connectors.
> > >
> > > Zell
> > > ___________________________________________
> > > https://mail.dworkin.nl/mailman/listinfo/dgd
> > >
> > 
> > 
> > ___________________________________________
> > https://mail.dworkin.nl/mailman/listinfo/dgd
> 
> ___________________________________________
> https://mail.dworkin.nl/mailman/listinfo/dgd


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