테이블을 1개를 추가하기 위해

버전 2에서 3로 바꾸고 했는데(한번은 컬럼 추가로 1에서2로 변경한 이력이 있습니다.)

계속 Can't upgrade read-only database from version 2 to 3: 이것이 떨어지네요..

도대체 뭐가 문제인지 모르겠습니다.

아래 소스 코드입니다.

public class DatabaseHelper extends SQLiteOpenHelper {
 
 private static final String DATABASE_NAME = "member.db";
    private static final int DATABASE_VERSION = 3;
 
    private static final String CREATE_MEMBER_TABLE = 
     "CREATE TABLE IF NOT EXISTS MT_MEMBER (" +
        "EMAIL TEXT PRIMARY KEY ," +
        "PASSWORD TEXT," +
        "MOBILE TEXT," +
        "NAME TEXT," +
        "JENDER TEXT," +
        "AUTO_YN TEXT" +
        ");";    
    private static final String CREATE_MEMBER_FILE_TABLE = 
        "CREATE TABLE IF NOT EXISTS MT_MEMBER_FILE (" +
        "FILE_INDEX TEXT PRIMARY KEY ," +
        "MEMBER_EMAIL TEXT PRIMARY KEY ," +
        "FILE_NAME TEXT," +
        "FILE_TYPE TEXT," +
        "FILE_PATH TEXT," +
        "FILE_ORIGIN_NAME TEXT," +
        "FILE_SIZE INTEGER," +
        "CREATE_DATE TEXT" +
        ");";
 
public DatabaseHelper(Context context) {
  super(context, DATABASE_NAME, null, DATABASE_VERSION);
  // TODO Auto-generated constructor stub
 }
    
 @Override
 public void onCreate(SQLiteDatabase db) {
  
  // Create the table
  db.execSQL(CREATE_MEMBER_TABLE);
  db.execSQL(CREATE_MEMBER_FILE_TABLE);
  
 }
 @Override
 public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
  // TODO Auto-generated method stub
  
  db.execSQL("drop table if exists MT_MEMBER");
  db.execSQL("drop table if exists MT_MEMBER_FILE");
  
  onCreate(db);
 }
 
@Override
 public void onOpen(SQLiteDatabase db) {
  // TODO Auto-generated method stub
  super.onOpen(db);
 }
 
}

잘못된 부분이 있나요???