Firstly BlackBerry supports three types of persistent storage: there is the MIDP records that are supported on J2ME phones, regular flat-file storage (which you would have to implement yourself completely) and the BlackBerry persistence model. You can only store byte arrays with the first two methods. The last method, the BB persistence model, essentially works like a giant hashtable - you provide a unique key the value you want to store, and you can then access it at a later date using the same key. The neat thing about this last approach is that the value you store can be any Java object, which is pretty useful.
two year ago, RIM announced that it was adding Sqlite to the BlackBerry API
refer this for how to use Sqlite