def insertDomain(self, domain, indegree=0, outdegree=0):
		'''增加一个域名'''
		cur = self.conn.cursor()
		cur.execute("INSERT INTO Domains VALUES (NULL,?,?,?)", (domain, indegree, outdegree))
		# 写入到文件中
		self.conn.commit()
def iqd_phasor(up, iqd, uqd, ax=0):
    """creates a phasor plot
    up: internal voltage
    iqd: current
    uqd: terminal voltage"""

    uxdq = (uqd[1]/np.sqrt(2), (uqd[0]/np.sqrt(2)-up))
    __phasor_plot(ax, up, (iqd[1]/np.sqrt(2), iqd[0]/np.sqrt(2)), uxdq)