Chapter 6: Error Handling

ADO uses several different methods to notify an application of errors that occur. This chapter discusses the types of errors that can occur when you are using ADO and how your application is notified. It concludes by making suggestions about how to handle those errors.

How Does ADO Report Errors?

ADO notifies you about errors in several ways:

• ADO errors generate a run-time error. Handle an ADO error the same way you would any other run-time error, such as using an On Error statement in Visual Basic.
• Your program can receive errors from OLE DB. An OLE DB error generates a run-time error as well.
• If the error is specific to your data provider, one or more Error objects are placed in the Errors collection of the Connection object that was used to access the data store when the error occurred.
• If the process that raised an event also produced an error, error information is placed in an Error object and passed as a parameter to the event. See Chapter 7: Handling ADO Events for more information about events.
• Problems that occur when processing batch updates or other bulk operations involving a Recordset can be indicated by the Status property of the Recordset. For example, schema constraint violations or insufficient permissions can be specified by RecordStatusEnum values.
• Problems that occur involving a particular Field in the current record are also indicated by the Status property of each Field in the Fields collection of the Record or Recordset. For example, updates that could not be completed or incompatible data types can be specified by FieldStatusEnum values.

The following sections describe each of these notification methods in more detail.