How to run background process in asp.net core 2.0

Question

Hi all,

 

i  am developing an application in asp.net core 2.0 where i am facing an issue thing is that user is uploading excel which contains 50000 thounsand records or even more here over all concept is that after uploading excel data i am saving in table a with all in one shot by using AddRange of entityframework core now after this i have to create two master table from this table now thing is that i want to enter data in these two table by background process but have no clue how to do it please give me any suggestion