When using SharePoint Designer I found this link that stepped me through how to get it working:
http://spsolution.blogspot.com/2008/12/how-to-insert-data-source-in-sharepoint.html
That allowed SharePoint Designer to talk to Oracle, but when I placed a data view on a page it gave me the following error:
Error while executing web part: System.Data.OracleClient.OracleException:
ORA-00923: FROM keyword not found where expected
at System.Data.OracleClient.OracleConnection.CheckError(OciErrorHandle errorHandle, Int32 rc)
at System.Data.OracleClient.OracleCommand.Execute(OciStatementHandle statementHandle, CommandBehavior behavior, Boolean needRowid, OciRowidDescriptor& rowidDescriptor, ArrayList& resultParameterOrdinals)
at System.Data.OracleClient.OracleCommand.Execute(OciStatementHandle statementHandle, CommandBehavior behavior, ArrayList& resultParameterOrdinals)
at System.Data.OracleClient.OracleCommand.ExecuteReader(CommandBehavior behavior)
at System.Data.OracleClient.OracleCommand.ExecuteDbDataReader(CommandBehavior behavior)
at System.Data.Common.DbCommand.Syst...
09/14/2009 14:40:23.52* w3wp.exe (0x0FA0)
0x1A88 Windows SharePoint Services Web Parts
89a1 Monitorable ...
em.Data.IDbCommand.ExecuteReader(CommandBehavior behavior)
at System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior)
at System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior)
at System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, String srcTable)
at System.Web.UI.WebControls.SqlDataSourceView.ExecuteSelect(DataSourceSelectArguments arguments)
at System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback)
at Microsoft.SharePoint.WebControls.SingleDataSource.GetXPathNavigatorInternal() ...
09/14/2009 14:40:23.52* w3wp.exe (0x0FA0)
0x1A88 Windows SharePoint Services Web Parts
89a1 Monitorable ...
at Microsoft.SharePoint.WebControls.SingleDataSource.GetXPathNavigator()
at Microsoft.SharePoint.WebControls.SingleDataSource.GetXPathNavigator(IDataSource datasource, Boolean originalData)
at Microsoft.SharePoint.WebPartPages.DataFormWebPart.GetXPathNavigator(String viewPath)
at Microsoft.SharePoint.WebPartPages.DataFormWebPart.PrepareAndPerformTransform()
I am mystified.