VB .Net Question:

System.Data.OleDB It contains the objects that we use to connect to a data source via an OleDB provider , such as OleDbConnection, OleDBCOmmand. System.Data.SqlClient It contains objects that we use to connect to a data source via Tabular data stream interface provided by Microsoft Sql Server. This can be generally used to provide better performance because it removes some of the intermediate layers required by the OleDB provider.