def query_byMac(mac):
     computerInfo = dbSession.query(ComputerInfo).filter(
         ComputerInfo.MACAddress == mac).first()
     if not computerInfo:
         return None
     else:
         return computerInfo
 def query_byIPv4(ipv4):
     computerInfo = dbSession.query(ComputerInfo).filter(
         ComputerInfo.IPv4Address == ipv4).first()
     if not computerInfo:
         return None
     else:
         return computerInfo
 def query_byMail(mail):
     computerInfo = dbSession.query(ComputerInfo).join(
         Employee, ComputerInfo.MACAddress == Employee.MACAddress).filter(
             Employee.mail == mail).first()
     if not computerInfo:
         return None
     else:
         return computerInfo
 def query_byMail(mail):
     vi = dbSession.query(VerifyInfo).filter(
         VerifyInfo.mail == mail).first()
     return vi
 def query_byMail(mail):
     employee = dbSession.query(Employee).filter(Employee.mail == mail).first()
     return employee