Disadvantages of storing session data in MySQL?

[eluser]Devyn[/eluser]
Thanks jedd!
I would like to explain a bit more of my game.
I'm writing a card game with multiplayer where 4 players can play like famous poker games.
I want to store the value of card that has been clicked and submitted by user. So I can calculate who wins.
Firstly, my problem is I don't know how to hide the value of the card so user cannot submit a value of the card which he doesn't have.
For example, I assigned the value of Club10 card to "C10". Following url is value of Player4's C10 card.
http://staging-colorfulcloud.aptanacloud...d16e7484f/C10
However, according to you and others, I got an idea that I can hash the value of "C10" so it'll be http://url/hash_session_id/hash_card
After that, I want to save that hash_card value in session table with related session_id.
If the user submit another hash_card, it'll be updated in session table again.
Am I flow make sense?