You might want to have a look at asp.net webapi which is built into asp.net MVC 4.
you don’t have to use that, but it is a nice way to do Ajaxy stuff. However, the basic idea is you GET/POST (using something like .post or .get in jquery) to an action (basically a URL). That action then takes care of storing things to a database.
You’ll want to learn about model binding and json…. thats the ability for asp.mvc to convert your C# objects to and from JSON
You’ll want to go and look at a number of asp.net mvc example apps, like nerd dinner, for examples of MVC and ajax…..
solved Insert Into using Ajax in ASP.net MVC [closed]