This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
I think the *.db file acts as the database in which all records have been stored, thus all your operation including reading,updating and finding records etc. must associate with this file directly or indirectly,depending on whether you use the cache technology.