Workspace.DefaultCursorDriver-Eigenschaft (DAO)

Gilt für: Access 2013, Office 2013

Syntax

Ausdruck . DefaultCursorDriver

Ausdruck Eine Variable, die ein Workspace-Objekt darstellt.

Hinweise

Die Einstellung oder der Rückgabewert kann auf eine der CursorDriverEnum -Konstanten festgelegt werden.

Diese Eigenschafteneinstellung wirkt sich nur auf Verbindungen aus, die nach dem Festlegen der Eigenschaft eingerichtet wurden. Das Ändern der DefaultCursorDriver-Eigenschaft hat keine Auswirkung auf vorhandene Verbindungen.

Beispiel

Dieses Beispiel zeigt mit der NextRecordset-Methode die Daten aus einer SELECT-Verbundabfrage an. Die DefaultCursorDriver-Eigenschaft muss beim Ausführen solcher Abfragen auf dbUseODBCCursor festgelegt sein. Die NextRecordset-Methode gibt auch dann True zurück, wenn einige oder alle der SELECT-Anweisungen keine Datensätze zurückgeben; False wird erst zurückgegeben, nachdem jede einzelne SQL-Klausel überprüft wurde.

    Sub NextRecordsetX() 
     
     Dim wrkODBC As Workspace 
     Dim conPubs As Connection 
     Dim rstTemp As Recordset 
     Dim intCount As Integer 
     Dim booNext As Boolean 
     
     ' Create ODBCDirect Workspace object and open Connection 
     ' object. The DefaultCursorDriver setting is required 
     ' when using compound SQL statements. 
     Set wrkODBC = CreateWorkspace("", _ 
     "admin", "", dbUseODBC) 
     wrkODBC.DefaultCursorDriver = dbUseODBCCursor 
     
     ' Note: The DSN referenced below must be set to 
     ' use Microsoft Windows NT Authentication Mode to 
     ' authorize user access to the Microsoft SQL Server. 
     Set conPubs = wrkODBC.OpenConnection("Publishers", , , _ 
     "ODBC;DATABASE=pubs;DSN=Publishers") 
     
     ' Construct compound SELECT statement. 
     Set rstTemp = conPubs.OpenRecordset("SELECT * " & _ 
     "FROM authors; " & _ 
     "SELECT * FROM stores; " & _ 
     "SELECT * FROM jobs") 
     
     ' Try printing results from each of the three SELECT 
     ' statements. 
     booNext = True 
     intCount = 1 
     With rstTemp 
     Do While booNext 
     Debug.Print "Contents of recordset #" & intCount 
     Do While Not .EOF 
     Debug.Print , .Fields(0), .Fields(1) 
     .MoveNext 
     Loop 
     booNext = .NextRecordset 
     Debug.Print " rstTemp.NextRecordset = " & _ 
     booNext 
     intCount = intCount + 1 
     Loop 
     End With 
     
     rstTemp.Close 
     conPubs.Close 
     wrkODBC.Close 
     
    End Sub 

Another way to accomplish the same task would be to create a prepared statement containing the compound SQL statement. The CacheSize property of the QueryDef object must be set to 1, and the Recordset object must be forward-only and read-only.

Sub NextRecordsetX2() 
 
 Dim wrkODBC As Workspace 
 Dim conPubs As Connection 
 Dim qdfTemp As QueryDef 
 Dim rstTemp As Recordset 
 Dim intCount As Integer 
 Dim booNext As Boolean 
 
 ' Create ODBCDirect Workspace object and open Connection 
 ' object. The DefaultCursorDriver setting is required 
 ' when using compound SQL statements. 
 Set wrkODBC = CreateWorkspace("", _ 
 "admin", "", dbUseODBC) 
 wrkODBC.DefaultCursorDriver = dbUseODBCCursor 
 
 ' Note: The DSN referenced below must be set to 
 ' use Microsoft Windows NT Authentication Mode to 
 ' authorize user access to the Microsoft SQL Server. 
 Set conPubs = wrkODBC.OpenConnection("Publishers", , , _ 
 "ODBC;DATABASE=pubs;DSN=Publishers") 
 
 ' Create a temporary stored procedure with a compound 
 ' SELECT statement. 
 Set qdfTemp = conPubs.CreateQueryDef("", _ 
 "SELECT * FROM authors; " & _ 
 "SELECT * FROM stores; " & _ 
 "SELECT * FROM jobs") 
 ' Set CacheSize and open Recordset object with arguments 
 ' that will allow access to multiple recordsets. 
 qdfTemp.CacheSize = 1 
 Set rstTemp = qdfTemp.OpenRecordset(dbOpenForwardOnly, _ 
 dbReadOnly) 
 
 ' Try printing results from each of the three SELECT 
 ' statements. 
 booNext = True 
 intCount = 1 
 With rstTemp 
 Do While booNext 
 Debug.Print "Contents of recordset #" & intCount 
 Do While Not .EOF 
 Debug.Print , .Fields(0), .Fields(1) 
 .MoveNext 
 Loop 
 booNext = .NextRecordset 
 Debug.Print " rstTemp.NextRecordset = " & _ 
 booNext 
 intCount = intCount + 1 
 Loop 
 End With 
 
 rstTemp.Close 
 qdfTemp.Close 
 conPubs.Close 
 wrkODBC.Close 
 
End Sub 
 

This example uses the RecordStatus and DefaultCursorDriver properties to show how changes to a local Recordset are tracked during batch updating. The RecordStatusOutput function is required for this procedure to run.

Sub RecordStatusX() 
 
 Dim wrkMain As Workspace 
 Dim conMain As Connection 
 Dim rstTemp As Recordset 
 
 Set wrkMain = CreateWorkspace("ODBCWorkspace", _ 
 "admin", "", dbUseODBC) 
 ' This DefaultCursorDriver setting is required for 
 ' batch updating. 
 wrkMain.DefaultCursorDriver = dbUseClientBatchCursor 
 
 ' Note: The DSN referenced below must be configured to 
 ' use Microsoft Windows NT Authentication Mode to 
 ' authorize user access to the Microsoft SQL Server. 
 Set conMain = wrkMain.OpenConnection("Publishers", _ 
 dbDriverNoPrompt, False, _ 
 "ODBC;DATABASE=pubs;DSN=Publishers") 
 
 ' The following locking argument is required for 
 ' batch updating. 
 Set rstTemp = conMain.OpenRecordset( _ 
 "SELECT * FROM authors", dbOpenDynaset, 0, _ 
 dbOptimisticBatch) 
 
 With rstTemp 
 .MoveFirst 
 Debug.Print "Original record: " & !au_lname 
 Debug.Print , RecordStatusOutput2(.RecordStatus) 
 
 .Edit 
 !au_lname = "Bowen" 
 .Update 
 Debug.Print "Edited record: " & !au_lname 
 Debug.Print , RecordStatusOutput2(.RecordStatus) 
 
 .AddNew 
 !au_lname = "NewName" 
 .Update 
 Debug.Print "New record: " & !au_lname 
 Debug.Print , RecordStatusOutput2(.RecordStatus) 
 
 .Delete 
 Debug.Print "Deleted record: " & !au_lname 
 Debug.Print , RecordStatusOutput2(.RecordStatus) 
 
 ' Close the local recordset without updating the 
 ' data on the server. 
 .Close 
 End With 
 
 conMain.Close 
 wrkMain.Close 
 
End Sub 
 
Function RecordStatusOutput(lngTemp As Long) As String 
 
 Dim strTemp As String 
 
 strTemp = "" 
 
 ' Construct an output string based on the RecordStatus 
 ' value. 
If lngTemp = dbRecordUnmodified Then _ 
 strTemp = "[dbRecordUnmodified]" 
 If lngTemp = dbRecordModified Then _ 
 strTemp = "[dbRecordModified]" 
 If lngTemp = dbRecordNew Then _ 
 strTemp = "[dbRecordNew]" 
 If lngTemp = dbRecordDeleted Then _ 
 strTemp = "[dbRecordDeleted]" 
 If lngTemp = dbRecordDBDeleted Then _ 
 strTemp = "[dbRecordDBDeleted]" 
 
 RecordStatusOutput = strTemp 
 
End Function