不幸的是，onupgrade drop命令在我的应用程序中不起作用

Question

我知道之前已经问过，但这些答案对我没有帮助。我的表一次又一次地添加以前插入的元素。我每次在另一个应用程序中发送插入值。如何停止或删除表。

private static final String DATABASE_NAME = "contactsManager";
private static final String TABLE_CONTACTS = "contacts";

 public void onCreate(SQLiteDatabase db) {

    String CREATE_CONTACTS_TABLE = "CREATE TABLE IF NOT EXISTS " + TABLE_CONTACTS + "("
            + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," + KEY_NAME + " TEXT,"
            + KEY_PH_NO + " TEXT," + KEY_PHOTO +" TEXT," + KEY_EMAIL_ID +" TEXT" + ")";
    db.execSQL(CREATE_CONTACTS_TABLE);
    //mDbHelper = new DatabaseHandler(mCtx);

}
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // Drop older table if existed

    db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);
    onCreate(db);
}