LINQ to ADO.NET (Portal Page)
LINQ to ADO.NET enables you to query over any enumerable object in ADO.NET by using the Language-Integrated Query (LINQ) programming model.
The LINQ to ADO.NET documentation is located in the ADO.NET section of the .NET Framework SDK: LINQ and ADO.NET.
There are three separate ADO.NET Language-Integrated Query (LINQ) technologies: LINQ to DataSet, LINQ to SQL, and LINQ to Entities. LINQ to DataSet provides richer, optimized querying over the DataSet, LINQ to SQL enables you to directly query SQL Server database schemas, and LINQ to Entities allows you to query an Entity Data Model.
LINQ to DataSet
The DataSet is one of the most widely used components in ADO.NET, and is a key element of the disconnected programming model that ADO.NET is built on. Despite this prominence, however, the DataSet has limited query capabilities.
LINQ to DataSet enables you to build richer query capabilities into DataSet by using the same query functionality that is available for many other data sources.
For more information, see LINQ to DataSet.
LINQ to SQL
LINQ to SQL provides a run-time infrastructure for managing relational data as objects. In LINQ to SQL, the data model of a relational database is mapped to an object model expressed in the programming language of the developer. When you execute the application, LINQ to SQL translates language-integrated queries in the object model into SQL and sends them to the database for execution. When the database returns the results, LINQ to SQL translates them back into objects that you can manipulate.
LINQ to SQL includes support for stored procedures and user-defined functions in the database, and for inheritance in the object model.
For more information, see LINQ to SQL.
LINQ to Entities
Through the Entity Data Model, relational data is exposed as objects in the .NET environment. This makes the object layer an ideal target for LINQ support, allowing developers to formulate queries against the database from the language used to build the business logic. This capability is known as LINQ to Entities. See LINQ to Entities for more information.