LINQ Namespace

In .NET framework history, Language INtegrated Query (LINQ) was added in CLR Version 2.0 SP1 and FW 3.5. It contains the database query integrated within the high level language like C#, VisualBasic, ASP .NET. We don't need to have a separate database access layer in the enterprise application architecture. LINQ allows you to perform type-safe queries over local and remote collections to sQL Server tables. A big advantage of LINQ is that it presents a consistent querying API across a variety of domains. The types of resolving LINQ queries reside in the below namespaces.

using System.Linq; // LINQ to In-memory Objects
using System.Xml.Linq; // LINQ to XML
using System.Data.Linq; // LINQ to SQL Server
using System.Data.Entity; // LINQ to Entity Framework
using System.Linq.Expressions // To build Expression Tree

LINQ to SQL Server and Entity Framework APIs leverage lower level ADO .NET types in System.Data namespace.