Programming Visual Basic .NET

Connecting to an OLE DB Data Source

OLE DB is a specification for wrapping data sources in a COM-based API so that data sources can be accessed in a polymorphic way. The concept is the same as ADO.NET’s concept of managed providers. OLE DB predates ADO.NET and will eventually be superseded by it. However, over the years, OLE DB providers have been written for many data sources, including Oracle, Microsoft Access, Microsoft Exchange, and others, whereas currently only one product—SQL Server—is natively supported by an ADO.NET managed provider. To provide immediate support in ADO.NET for a wide range of data sources, Microsoft has supplied an ADO.NET managed provider for OLE DB. That means that ADO.NET can work with any data source for which there is an OLE DB data provider. Furthermore, because there is an OLE DB provider that wraps ODBC (an even older data-access technology), ADO.NET can work with virtually all legacy data, regardless of the source.

Connecting to an OLE DB data source is similar to connecting to SQL Server, with a few differences: the OleDbConnection class (from the System.Data.OleDb namespace) is used instead of the SqlConnection class, and the connection string is slightly different. When using the OleDbConnection class, the connection string must specify the OLE DB provider that is to be used as well as additional information that tells the OLE DB provider where the actual data is. For example, the following code opens a connection to the Northwind sample database ...