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 getProvides(self):
		"""Fetch a spec file from pkgdb and get provides from all its [sub]packages"""
		if self.sp_obj == None:
			return {}

		return self.sp_obj.getProvides()