def close(self):
		'''关闭与数据库的连接'''
		if VERBOSE:
			print 'Database connection CLOSE.'
		self.conn.close()
def line(self, x, y, length, horizontal):
		if horizontal:
			self.board[y,x:x+length] = self.color
		else:
			self.board[y:y+length,x] = self.color