LINQ itself doesn't have anything directly to do with SQL. It's a mechanism for composing expression trees that are compiled into your application. At runtime a

LINQ itself doesn't have anything directly to do with SQL. It's a mechanism for composing expression trees that are compiled into your application. At runtime a LINQ query provider can walk the expression tree and translate it into a query for the underlying data store. It's a very very powerful concept, but IME it doesn't get used all that much for things other than SQL because writing a query provider is a lot of work. Anyway, the typical C# ORM is Entity Framework, which includes the LINQ-to-Entities query provider.