Android Room 數據庫升級

1、修改版本號1–>2
@Database(entities = {HomeDataBean.class}, version = 1, exportSchema = false)

2、addMigrations，表明數據庫、表的變動情況

			Room
                .databaseBuilder(context, DatabaseConfig.class, DB_NAME)
                .allowMainThreadQueries()
                //.addMigrations(MIGRATION_1_2)
                .build();

	 /**
     * 數據庫版本 1->2
     */
    static final Migration MIGRATION_1_2 = new Migration(1, 2) {
        @Override
        public void migrate(SupportSQLiteDatabase database) {
        	//指明數據庫的變動情況
            //database.execSQL("ALTER TABLE user " + " ADD COLUMN age INTEGER");
        }
    };