You can use some webservice,
http://csharpdotnetfreak.blogspot.com/2009/04/trace-mobile-location-operator-number.html
http://mrintech.com/trace-mobile-number-location-missed-calls-india
If you store in database means how much data you will store? otherwise you can do one thing, store 1st 4 digit of the mobile number in database, from that you can get the operator name and state code, if you want pincode means then you should use some webservices