LINQ Architecture

LINQ Architecture in .NET

LINQ has a 3-layered architecture in which the uppermost layer consists of the language extensions and the bottom layer consists of data sources that are typically objects implementing IEnumerable<T> or IQueryable<T> generic interfaces. The architecture is shown below in Figure.

LINQ to Objects deals with in-memory data. Any class that implements the IEnumerableinterface (in the System.Collections.Generic namespace) can be queried with Standard Query Operators.

LINQ to ADO.NET (also known as LINQ enabled ADO .NET) deals data from external sources, basically anything ADO.NET can connect to. Any class that implements IEnumerableor IQueryable (in the System.Query namespace) can be queried with Standard Query Operators. The LINQ to ADO.NET functionality could be achieved by using System.Data.Linq namespace.

LINQ to XML is a comprehensive API for in-memory XML programming. Like the rest of LINQ, it includes Standard Query Operators, and it can also be used in concert with LINQ to ADO.NET, but its primary purpose is to unify and simplify the kinds of things that disparate XML tools, like XQuery, XPath and XSLT are typically used to do. The LINQ to XML functionality could be achieved by using System.Xml.Linq namespace.