android 数据库升级（保留原先数据）

在onUpgrade（）中处理

 db.execSQL("CREATE TABLE " + "'post2' (" + //post2 为暂存文件名，可以在这里添加字段或者删除字段 "'_id' INTEGER PRIMARY KEY ," + "'SONG_ID' INTEGER UNIQUE ," + "'SONG_NAME' TEXT," + "'LISTEN_FILE' TEXT," + "'ARTIST_NAME' TEXT," + "'HAS_PLAYED' INTEGER ," + "'ARTIST_URL' TEXT," + "'IS_SLOW_TYPE' INTEGER," + "'SONG_TIME' INTEGER ," + "'IS_MUSIC_POWER' INTEGER ," + "'HAS_COLLECTED' INTEGER);"); 

            ／／将原先ＬＯＡＤＥＤ＿ＳＯＮＧ　表中中的响应字段的数据ｃｏｐｙ到ｐｏｓｔ２表中
            db.execSQL("INSERT INTO post2 (_id, SONG_ID, SONG_NAME, LISTEN_FILE, ARTIST_NAME, HAS_PLAYED, ARTIST_URL,IS_SLOW_TYPE, SONG_TIME, IS_MUSIC_POWER,HAS_COLLECTED)" + " SELECT _id, SONG_ID, SONG_NAME, LISTEN_FILE, ARTIST_NAME,HAS_PLAYED, ARTIST_URL, IS_SLOW_TYPE, SONG_TIME, IS_MUSIC_POWER ,HAS_COLLECTED FROM LOADED_SONG;");
            ／／删除原先的表
            db.execSQL("DROP TABLE LOADED_SONG"); ／／重命名表 db.execSQL("ALTER TABLE post2 RENAME TO LOADED_SONG"); ／／也可以在新表中添加字段 db.execSQL("ALTER TABLE LOADED_SONG ADD COLUMN USERNAME TEXT");