Android数据库Room框架升级

创建Migration

static final Migration MIGRATION_1_2 = new Migration(1, 2) {
        @Override
        public void migrate(SupportSQLiteDatabase database) {
            //在表device_init中添加TEXT字段mimc
            database.execSQL("ALTER TABLE device_init"
                    + " ADD COLUMN mimc TEXT");
            //在表device_init中添加TEXT字段appId
            database.execSQL("ALTER TABLE device_init"
                    + " ADD COLUMN appId TEXT");
            //创建新表connect_prod并添加对应的字段
            //PRIMARY KEY(id)将id设置为主键，NOT NULL设置对应的键不能为空
            database.execSQL("CREATE TABLE connect_prod(icon TEXT,local_file_path TEXT,action_res TEXT,url TEXT,idx TEXT,thumb_image_url TEXT," +
                    "title TEXT,name TEXT,online TEXT,down TEXT,type TEXT,down_load_complete INTEGER NOT NULL,id TEXT NOT NULL,res TEXT,PRIMARY KEY(id))");
        }
    };

在数据库中添加Migration

{
        Room.databaseBuilder(context.getApplicationContext(),
                             HuLianDatabase.class, "RoomUse.db")
                             .addMigrations(MIGRATION_1_2)
                             .build();
}