通过查询sql数据库发送警报

I have created a windows service which will query sql table and check for last 3 minutes data to decide the status of device using the same if all data is zero the device is zero its considered to be off other wise on if no data is present device is offline. But the problem I'm facing is windows service has to query database very frequently is there any alternative way to do this. I have created a windows service which will que