once you start treating the database as tables with relationships -- rather than as disjoint flat structures -- you'll be able to put in all sorts of such game logic just using sql statements. i'm not shouting from the altar...merely saying that a more thought out and normalized database will be much easier to use, especially if the game is going to be non-trivial. whereas game/database logic expressed in code becomes increasingly difficult to debug/maintain, as rules/relationships are added. If you don't know already about 3rd normal form (databases,) learning it becomes a lifelong asset in any database work.
all the best with your game