What is LINQ?

LINQ is an acronym of Language Integrated Query.

As the name suggests LINQ is a query language which can be integrated with .Net code, LINQ is Microsoft’s approach to combine .Net code and the query language in a single place.

In the conventional approach we will defined the User interface elements in the Windows or Web interface, the data will be stored in the database and we use queries or stored procedures to fetch the data into the User interface, this required the developer to be aware of both the User Interface programming and the database query programming.

With LINQ the queries can be integrated with the .Net code, hence the developer need not be aware of SQL queries; he can use LINQ queries instead and fetch data from the data sources to use it in the UI.

LINQ offers powerful data binding, which enables us to link to multiple types of data sources, at present LINQ supports the following data sources.

          

  LINQ to Object  - Collection of in-memory (Array, List etc)
  LINQ to SQL       - Relational databases SQL Server
  LINQ to DataSet - ADO.Net DataTable and DataSet objects
  LINQ to XML      - XML files and in-memory XML strings
  LINQ to Entities   - Querying Entity Data Model entities 

The advantage of using LINQ is that the LINQ queries remain same irrespective of whatever data source is used, in conventional methods each of these data sources will have to be queried using its own way, LINQ standardizes this and makes it easier for the developer to query multiple data sources using the same standard LINQ.