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Thread: mmo question

  1. #1

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    mmo question

    Can anyone give an example of how most mmo's handle data? I mean if the server side have a database running, how does the client communicate with that database. Is the same database used for login information and etc.? any and all info on this is welcome.

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    I'm about to be a PowerPoster! Hack's Avatar
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    Re: mmo question

    Mmo?

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    Super Moderator si_the_geek's Avatar
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    Re: mmo question

    "Massively Multiplayer Online" game.


    The answer to your question is pretty much non existent - each system is designed in the way that the people who created/extended it thought would be best, and they don't tend to make that information public.

    I expect it would be extremely unusual for the client to have direct access to the database tho, as that makes it extremely easy for cheaters/hackers to do whatever they want. Most likely is that there is some kind of program on the server which they link to, and that program does the necessary work with the database.

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    G&G Moderator chemicalNova's Avatar
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    Re: mmo question

    Your basic protocol consists of "queries" the client sends to the server, which translates this into proper query language being used, queries the DB, then sends the data back to the client.

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    Fanatic Member technorobbo's Avatar
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    Re: mmo question

    Quote Originally Posted by frozenbrain
    Can anyone give an example of how most mmo's handle data? I mean if the server side have a database running, how does the client communicate with that database. Is the same database used for login information and etc.? any and all info on this is welcome.
    I think that Firts Person Shooters (FPS) use a peer to peer arrangement during game play. Where one of the players is the traffic cop directing traffic. That explains why when your playing COD4 and the host leaves the game crashes.

    In an MMO the Server has to contain the information during game play. Because , not to be facetious, it's Massive!!!

    In both cases there's some administrative duties that the game server handles, such as keeping track of your level, your trophies and finding you a match.

    For the smaller games you could use a UDP protocol to keep bandwidth low. After all your not doing banking transactions.

    I did write an online chess game (many moons ago) and I used a Perl program on the ISP's server to find a match and UDP between the players once they found each other. I changed ISP's and my new one didn't allow Perl scripts so I abandoned the whole thing.

    Post Edited:

    I'm sorry I should have mentioned that UDP, unlike TCP/IP, does not actualy keep a continous connection going. That requires some handshaking and an occasional "heartbeat" token sent between players so they know who's still there.
    Last edited by technorobbo; Jan 25th, 2009 at 11:14 AM.
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    Re: mmo question

    FYI. First person shooters like COD use a client-server architecture, which is what you describe, but is not peer-to-peer.

    Peer-to-peer is when each computer is responsible for updating their state, sending this information to other clients. The crucial bit is that no one computer is responsible for checking the data the other computers are sending.
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    Fanatic Member technorobbo's Avatar
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    Re: mmo question

    Peer to Peer is when the information passes directly between players computers causing the game to end when the message "Host Ended Game". Often you can see other players lagging without affecting the game, but when the host starts to lag the game totally bogs down. The Client Server is a classic bottle-neck architecture, which would be fantastic cause the game,in theory, would never lag. The discussion boards for COD4 were always buzzing cause COD4 would not switch hosts when one left, it would just shut down the game. The host on COD4 really has no control - his computer just drew the lucky straw.
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