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C# Learning: LINQ Concept

LINQ means Language-INtegrated Query.

Before LINQ, we had to juggle different languages like SQL, XML, or XPath
along with various technologies and APIs like ADO.NET or System.Xml in every
application written using general-purpose languages such as C# or VB.NET. It goes
without saying that this approach had several drawbacks.1 LINQ glues several
worlds together. It helps us avoid the bumps we would usually find on the road
from one world to another: using XML with objects, objects with relational data,
and relational data with XML are some of the tasks that LINQ will simplify.
One of the key aspects of LINQ is that it was designed to be used against any
type of object or data source and to provide a consistent programming model for
doing so.

The syntax and concepts are the same across all of its uses: Once you
learn how to use LINQ against an array or a collection, you also know most of the
concepts needed to take advantage of LINQ with a database or an XML file.
Another important aspect of LINQ is that when you use it, you work in a
strongly typed world. The benefits include compile-time checking for your queries
as well as nice hints from Visual Studio’s IntelliSense feature.
LINQ will significantly change some aspects of how you handle and manipulate
data with your applications and components. You will discover how LINQ is a step
toward a more declarative programming model. Maybe you will wonder in the
not-so-distant future why you used to write so many lines of code.
There is duality in LINQ. You can conceive of LINQ as consisting of two complementary
parts: a set of tools that work with data, and a set of programming language


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