OleDbConnection Class

An OleDbConnection object represents a unique connection to a data source. With a client/server database system, it is equivalent to a network connection to the server. Depending on the functionality supported by the native OLE DB provider, some methods or properties of an OleDbConnection object may not be available.

When you create an instance of OleDbConnection, all properties are set to their initial values. For a list of these values, see the OleDbConnection constructor.

You can open more than one DataReader on a single OleDbConnection. If the OLE DB provider you use does not support more than one DataReader on a single connection, the provider implicitly opens an additional connection for each.

If the OleDbConnection goes out of scope, it is not closed. Therefore, you must explicitly close the connection by calling Close or Dispose, or by using the OleDbConnection object within a Using statement.

Note
To deploy high-performance applications, you must use connection pooling. When you use the .NET Framework Data Provider for OLE DB, you do not have to enable connection pooling because the provider manages this automatically. For more information about how to use connection pooling with the .NET Framework Data Provider for OLE DB, see OLE DB, ODBC, and Oracle Connection Pooling (ADO.NET).

If a fatal OleDbException (for example, a SQL Server severity level of 20 or greater) is generated by the method executing an OleDbCommand, the OleDbConnection might be closed. However, the user can reopen the connection and continue.

An application that creates an instance of the OleDbConnection object can require all direct and indirect callers to have sufficient permission to the code by setting declarative or imperative security demands. OleDbConnection makes security demands using the OleDbPermission object. Users can verify that their code has sufficient permissions by using the OleDbPermissionAttribute object. Users and administrators can also use the Caspol.exe (Code Access Security Policy Tool) to modify security policy at the computer, user, and enterprise levels. For more information, see Code Access Security and ADO.NET.

For more information about handling warning and informational messages from the data server, see Connection Events (ADO.NET).

Note
The OleDbConnection object does not support setting or retrieving dynamic properties specific to an OLE DB provider. Only properties that can be passed in the connection string for the OLE DB provider are supported.

The following example creates an OleDbCommand and an OleDbConnection. The OleDbConnection is opened and set as the Connection for the OleDbCommand. The example then calls ExecuteNonQuery and closes the connection. To accomplish this, ExecuteNonQuery is passed a connection string and a query string that is an SQL INSERT statement.

public void InsertRow(string connectionString, string insertSQL)
{
    using (OleDbConnection connection = new OleDbConnection(connectionString))
    {
        // The insertSQL string contains a SQL statement that
        // inserts a new row in the source table.
        OleDbCommand command = new OleDbCommand(insertSQL);

        // Set the Connection to the new OleDbConnection.
        command.Connection = connection;

        // Open the connection and execute the insert command.
        try
        {
            connection.Open();
            command.ExecuteNonQuery();
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }
        // The connection is automatically closed when the
        // code exits the using block.
    }
}

.NET Framework

.NET Framework Client Profile

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

Other Resources