Room Android - 如何处理数据库版本升级

Question

我正在阅读关于Android架构组件的房间,并想知道Room中是否存在与SQLiteOpenHelper中可用的onUpgrade方法等效的内容 -

@Override public void onUpgrade(最终的SQLiteDatabase数据库,final int oldVersion,final int newVersion){}

谢谢,RS.

Answer 1

您可以使用https://developer.android.com/training/data-storage/room/migrating-db-versions.html

 Room.databaseBuilder(getApplicationContext(), MyDb.class, "database-name")
            .addMigrations(MIGRATION_1_2,MIGRATION_1_3, MIGRATION_2_3).build();

    static final Migration MIGRATION_1_2 = new Migration(1, 2) {
        @Override
        public void migrate(SupportSQLiteDatabase database) {
            database.execSQL("CREATE TABLE `Fruit` (`id` INTEGER, "
                    + "`name` TEXT, PRIMARY KEY(`id`))");
        }
    };

    static final Migration MIGRATION_2_3 = new Migration(2, 3) {
        @Override
        public void migrate(SupportSQLiteDatabase database) {
            database.execSQL("ALTER TABLE Book "
                    + " ADD COLUMN pub_year INTEGER");
        }
    };

   static final Migration MIGRATION_1_3 = new Migration(1, 3) {
            @Override
            public void migrate(SupportSQLiteDatabase database) {
                database.execSQL("ALTER TABLE Book "
                        + " ADD COLUMN pub_year INTEGER");
            }
        };