Language Integrated Query (LINQ), which unifies the way data can be retrieved in .NET. LINQ provides a uniform way to retrieve data from any object that implements the IEnumerable
LINQ-enabled languages can provide full type-safety and compile-time checking of query expressions, and development tools can provide full intellisense, debugging, and rich refactoring support when writing LINQ code.
LINQ is a series of language extensions that supports data querying in a type-safe way; it will be released with the next version Visual Studio, VS2008, code-named "Orcas."
The data to be queried can take the form of XML (LINQ to XML), databases (LINQ-enabled ADO.NET, which includes LINQ to SQL, LINQ to Dataset and LINQ to Entities), objects (LINQ to Objects) etc.
LINQ is a uniform programming model for any kind of data. LINQ enables you to query
and manipulate data with a consistent model that is independent from data sources.
LINQ is just another tool for embedding SQL queries into code.
LINQ is yet another data abstraction layer.
LINQ is a methodology that simplifies and unifies the implementation of any kind of data access. LINQ does not force you to use a specific architecture; it facilitates the implementation of several existing architectures for accessing data. As with every tool, it can be used in both good and in bad ways. To get the most out of LINQ, you will have to master it.