There are several sets of objects for accessing a data source:
Objects prefixed
OleDb (from the
System.Data.OleDb namespace) use an OLEDB provider to access that data store.
Objects prefixed
Odbc (from the
System.Data.Odbc namespace) use an ODBC driver to access that data store.
Objects prefixed
Oracle (from the
System.Data.OracleClient namespace) use an Oracle- specific provider to access that data store.
Objects prefixed
Sql (from the
System.Data.SqlClient namespace) use the Microsoft SQL Server Tabular Data Stream (TDS) interface to access that data store.
In general, the
Sql -prefixed objects are much faster and more efficient, and should always be used where you know that the data store will be Microsoft SQL Server. All the data access classes automatically provide connection pooling.