I'm not sure you can add it to the cheat.db file, but you can put it in a text file like so:
.........................................
;Game ID: YT9E-33E0FA2C
;Name of Game here not really important
;There are XX codes for this game.
Code:
03807d40 ebafd8af
.........................................
Type the stuff b/t the ".............." and you're set. Then point the game to the cheat file.
You can find the Game Id from codejunkies.