本范例演示从 Command 和 Connection 对象运行 Execute 方法。范例中还使用 Requery 方法检索 Recordset 中的当前数据,并用 Clear 方法清除 Errors 集合的内容。(通过 Recordset 的 ActiveConnection 属性的 Connection 对象来访问 Errors 集合。)运行此过程需要 ExecuteCommand 和 PrintOutput 过程。
Public Sub ExecuteX()
Dim strSQLChange As String
Dim strSQLRestore As String
Dim strCnn As String
Dim cnn1 As ADODB.Connection
Dim cmdChange As ADODB.Command
Dim rstTitles As ADODB.Recordset
Dim errLoop As ADODB.Error
' Define two SQL statements to execute as command text.
strSQLChange = "UPDATE Titles SET Type = " & _
"'self_help' WHERE Type = 'psychology'"
strSQLRestore = "UPDATE Titles SET Type = " & _
"'psychology' WHERE Type = 'self_help'"
' Open connection.
strCnn = "Provider=sqloledb;" & _
"Data Source=srv;Initial Catalog=Pubs;User Id=sa;Password=; "
Set cnn1 = New ADODB.Connection
cnn1.Open strCnn
' Create command object.
Set cmdChange = New ADODB.Command
Set cmdChange.ActiveConnection = cnn1
cmdChange.CommandText = strSQLChange
' Open titles table.
Set rstTitles = New ADODB.Recordset
rstTitles.Open "titles", cnn1, , , adCmdTable
' Print report of original data.
Debug.Print _
"Data in Titles table before executing the query"
PrintOutput rstTitles
' Clear extraneous errors from the Errors collection.
cnn1.Errors.Clear
' Call the ExecuteCommand subroutine to execute cmdChange command.
ExecuteCommand cmdChange, rstTitles
' Print report of new data.
Debug.Print _
"Data in Titles table after executing the query"
PrintOutput rstTitles
' Use the Connection object's execute method to
' execute SQL statement to restore data. Trap for
' errors, checking the Errors collection if necessary.
On Error GoTo Err_Execute
cnn1.Execute strSQLRestore, , adExecuteNoRecords
On Error GoTo 0
' Retrieve the current data by requerying the recordset.
rstTitles.Requery
' Print report of restored data.
Debug.Print "Data after executing the query " & _
"to restore the original information"
PrintOutput rstTitles
rstTitles.Close
cnn1.Close
Exit Sub
Err_Execute:
' Notify user of any errors that result from
' executing the query.
If rstTitles.ActiveConnection.Errors.Count >= 0 Then
For Each errLoop In rstTitles.ActiveConnection.Errors
MsgBox "Error number: " & errLoop.Number & vbCr & _
errLoop.Description
Next errLoop
End If
Resume Next
End Sub
Public Sub ExecuteCommand(cmdTemp As ADODB.Command, _
rstTemp As ADODB.Recordset)
Dim errLoop As Error
' Run the specified Command object. Trap for
' errors, checking the Errors collection if necessary.
On Error GoTo Err_Execute
cmdTemp.Execute
On Error GoTo 0
' Retrieve the current data by requerying the recordset.
rstTemp.Requery
Exit Sub
Err_Execute:
' Notify user of any errors that result from
' executing the query.
If rstTemp.ActiveConnection.Errors.Count > 0 Then
For Each errLoop In Errors
MsgBox "Error number: " & errLoop.Number & vbCr & _
errLoop.Description
Next errLoop
End If
Resume Next
End Sub
Public Sub PrintOutput(rstTemp As ADODB.Recordset)
' Enumerate Recordset.
Do While Not rstTemp.EOF
Debug.Print " " & rstTemp!Title & _
", " & rstTemp!Type
rstTemp.MoveNext
Loop
End Sub