LINQ defines standard query operators that allow code written in LINQ-enabled languages to filter, enumerate, and create projections of several types of collections using the same syntax. Such collections may include arrays, enumerable classes, XML, datasets from relational databases, and third party data sources. The LINQ project uses features of version 2.0 of the .NET Framework, new LINQ-related assemblies, and extensions to the C# and Visual Basic .NET languages. Microsoft has distributed a preview release of LINQ, consisting of those libraries and compilers for C# 3.0 and Visual Basic 9. Other languages, such as F# and Nemerle, have also announced preliminary support.

The .NET Framework 3.5 provides the foundation for building connected and appealing applications, productively, on a wide variety of systems from the device to the data center.

Microsoft continues to support developers using the .NET Framework platform by providing support for applications built in previous versions to the 3.5 release, so existing applications built for .NET Framework 2.0 or .NET Framework 3.0 will continue to work.

The .NET Framework 3.5 adds new features in several major technology areas:

• Deep integration of Language Integrated Query (LINQ) and data awareness.
• Support for Web 2.0 AJAX-style applications and services in ASP.NET and WCF.
• Full tooling support for WF, Windows Communication Foundation (WCF), and Windows Presentation Foundation (WPF), including the new workflow-enabled services technology.
• New classes in the base class library (BCL) for the .NET Framework 3.5 address the most common customer requests.

Structured Query Language. The standardized relational database language for defining database objects and manipulating data.

It executes low-level instruction generated by compiler.

It translates DML statements in a query language into low-level instruction that the query evaluation engine can understand.

It is procedural query language. It consists of a set of operations that take one or two relations as input and produce a new relation.