SQL Server and ADO.NET
This section describes features and behaviors that are specific to the .NET Framework Data Provider for SQL Server (System.Data.SqlClient).
System.Data.SqlClient provides access to versions of SQL Server, which encapsulates database-specific protocols. The functionality of the data provider is designed to be similar to that of the .NET Framework data providers for OLE DB, ODBC, and Oracle. System.Data.SqlClient includes a tabular data stream (TDS) parser to communicate directly with SQL Server.
To use the .NET Framework Data Provider for SQL Server, an application must reference the System.Data.SqlClient namespace.
For complete documentation of the SQL Server Database Engine, see SQL Server Books Online for the version of SQL Server you are using.