Propriedade Workspace.DefaultCursorDriver (DAO)

Aplica-se ao: Access 2013, Office 2013

Sintaxe

expressão . DefaultCursorDriver

expressão Uma variável que representa um objeto Workspace.

Comentários

A configuração ou o valor de retorno pode ser definido como uma das constantes CursorDriverEnum.

Essa configuração de propriedade afeta somente as conexões estabelecidas após a definição da propriedade. Alterar a propriedade DefaultCursorDriver não afeta as conexões existentes.

Exemplo

Este exemplo usa o método NextRecordset para visualizar os dados de uma consulta SELECT composta. A propriedade DefaultCursorDriver deve estar definida como dbUseODBCCursor ao executar essas consultas. O método NextRecordset retornará True mesmo se algumas ou todas as instruções SELECT retornarem registros em branco; ele retornará False somente após a verificação de todas as cláusulas SQL individuais.

    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 

Outra forma de cumprir a mesma tarefa é criar uma instrução preparada contendo a instrução SQL composta. A propriedade CacheSize do objeto QueryDef deve ser definida como 1, e o objeto Recordset deve ser somente encaminhamento e somente leitura.

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 
 

Este exemplo usa as propriedades RecordStatus e DefaultCursorDriver para mostrar como as alterações para um Recordset local são controladas durante uma atualização em lote. A função RecordStatusOutput é exigida para que este procedimento seja executado.

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