Database support is the lifeline of every application, big or small. Unless your application deals only with simple data, you need a database system to store your structured data. Android uses the SQLite database system, which is an open-source, stand-alone SQL database, widely used by many popular applications. For example, Mozilla Firefox uses SQLite to store configuration data and iPhone also uses SQLite for database storage.
In Android, the database that you create for an application is only accessible to itself; other applications will not be able to access it. Once created, the SQLite database is stored in the /data/data/