How to populate Android Room database table on first run?

Updated

You can do this in 3 ways: important check this for migration details

1- Populate your database from exported asset schema

Room.databaseBuilder(appContext, AppDatabase.class, "Sample.db")
    .createFromAsset("database/myapp.db")
    .build();

2- Populate your database from file

Room.databaseBuilder(appContext, AppDatabase.class, "Sample.db")
    .createFromFile(new File("mypath"))
    .build();

3- You can run scripts after database is created or run every time database is opened using RoomDatabase.Callback, this class is available in the latest version of the Room library.

You need to implement onCreate and onOpen method of RoomDatabase.Callback and add it to RoomDatabase.Builder as shown below.

yourDatabase = Room.databaseBuilder(context, YourDatabase.class, "your db")
    .addCallback(rdc)
    .build();

RoomDatabase.Callback rdc = new RoomDatabase.Callback() {
    public void onCreate (SupportSQLiteDatabase db) {
        // do something after database has been created
        
    }
    public void onOpen (SupportSQLiteDatabase db) {
        // do something every time database is open
     
    }
};

Reference

You can use Room DAO itself in the RoomDatabase.Callback methods to fill the database. For complete examples see Pagination and Room example

   RoomDatabase.Callback dbCallback = new RoomDatabase.Callback() {
        public void onCreate(SupportSQLiteDatabase db) {
            Executors.newSingleThreadScheduledExecutor().execute(new Runnable() {
                @Override
                public void run() {
                   getYourDB(ctx).yourDAO().insertData(yourDataList);
                }
            });
        }
    };