To use the database, select the category that you want to sort by and either start typing the name of the game, or scroll down until you find it. Then click on your game.
In the extra comments you will see stores mentioned like (Steam) or (Amazon) This indicates where the person who added this game bought the game. Since there's sometimes different forms of DRM at different stores, your best results will be the ones that match the store you are shopping at. The information can be relevant for the other stores too, but more accurate information is always better. If you contribute a game to the database, please add the store that you bought it from in parenthesis in the comments section. Thanks!