Just make sure that whatever DBMS you use, you use an abstract interface to hide the implementation. That way, if MySQL stops meeting your needs, you can easily replace it (with Oracle for example). Here''s a really rough example:
class IDatabase
{
virtual ~IDatabase ( void ) {}
virtual void SetConnectionInfo ( char * db, char * user, char * pw ) = 0;
virtual int Query ( char * sql ) = 0;
..
}
Then each database implementation would extend this interface and new implementations could be created with a DBMS factory class like so:
DBMSFactory dbmsFactory;
DBMS *dbms = dbmsFactory.Create ( "mysql" );
char* sql[] = "DELETE FROM accounts WHERE ID=1";
dbms->SetConnectionInfo ( "mmorpg", "root", "" );
dbms->Query ( sql );
dbmsFactory.Destroy ( dbms );
Another cool idea would be to make your factory a singleton so that you could call it from anywhere to get an instance of your dbms. The book C++ Programming for Game Developers has a really good chapter on abstraction which explains this in more detail.
bpopp (
bpopp.net)
Anyway. I''m pondering over the backend database/s for a MMO and am currently wondering how many actual databases there are? Does one need a separate computer with it''s own database for every different WORLD in a game plus a separate database for accout information?
Or will one really nice computer holding a single massive database get the job done?
I''m thinking of a preliminary design that some entities would be
ACCOUT
Accounts have user information and account information and character information. Each character is also a specific entity. An account can have characters on multiple WORLDs sooo.
Or if a single machine for each world then one database to store account information and another DB for each world so when a client logs in, the login server presents a list of active WORLDS and the client selects a world and is then handed off to a new computer and new database. This new database has all information about the characters this client has on this server.
The single database for everything model would be the easiest to setup as far as communication and data backup but I''m wondering is a single database will be able to work quickly enough?
All logins, game saves, inventory loading, everything going through one master computer and master database. Of course is the network connection and computer holding it is fast enough I suppose it is possible. I''m just which solution is more viable?
Thanks,
Webby AKA TheQuestionGuy 
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