public void close()
        {
            if (isOpen())
            {
                this.db.Close();

            }
            this.db = null;
        }
        public override void open(string name)
	    {
		    close();
            if (name != null && getDirectory() != null)
            {
		        try
                {
                    string path = Path.Combine(getDirectory(), name);
                    db = new Database(path);
                }
                catch (SQLiteException)
                {
                    db = null;
                }
            }
	    }
 public void open(string path)
 {
     close();
     try
     {
         db = new Database(path);
     }
     catch (SQLiteException)
     {
         db = null;
     }
 }