ASP.net core connectionstring issue

I am developing an application in asp.net core and client has given me reuirement tool as asp.net core and i am plane mvc developer so can any body guide me to get complete idea of asp.net core with database connectivity i.e how to create and use coonection string in asp.net core and how to make database coonectivity in asp.net core as for as i have done research i think we need dbcontext and can not use raw sql queries in asp.net mvc please help me waiting for reply