73.7 In-Memory Databases

The examples outlined in this chapter involved the use of a SQLite database that exists as a database file on the persistent storage of an Android device. This ensures that the data persists even after the app process is terminated.

The Room database persistence library also supports in-memory databases. These databases reside entirely in memory and are lost when the app terminates. The only change necessary to work with an in-memory database is to call the Room.inMemoryDatabaseBuilder() method of the Room Database class instead of Room.databaseBuilder(). The following code shows the difference between the method calls (note that the in-memory database does not require a database name):

// Create a file storage based database

INSTANCE = Room.databaseBuilder<CustomerRoomDatabase>(context.applicationContext,

        CustomerRoomDatabase::class.java, "customer_database")

   ...