This chapter covered LINQ to SQL features used to query data. With LINQ to SQL, you can query a relational structure stored in a SQL Server database so that you can convert LINQ queries into native SQL queries and access UDFs and stored procedures if required. LINQ to SQL handles entity classes that map an underlying physical database structure through attributes or external XML files. Stored procedures and UDFs can be mapped to methods of a class representing a SQL Server database. LINQ to SQL supports most of the basic LINQ features that you saw in Chapter 3.