IsolationLevel 和 Mode 屬性範例 (VB)
這個範例會使用 Mode 屬性來開啟獨佔連線,而 IsolationLevel 屬性則會開啟與其他交易隔離進行的交易。
'BeginIsolationLevelVB
'To integrate this code
'replace the data source and initial catalog values
'in the connection string
Public Sub Main()
On Error GoTo ErrorHandler
Dim Cnxn As ADODB.Connection
Dim rstTitles As ADODB.Recordset
Dim strCnxn As String
Dim strSQLTitles As String
' Open connection
Set Cnxn = New ADODB.Connection
strCnxn = "Provider='sqloledb';Data Source='MySqlServer';" & _
"Initial Catalog='Pubs';Integrated Security='SSPI';"
Cnxn.Mode = adModeShareExclusive
Cnxn.IsolationLevel = adXactIsolated
Cnxn.Open strCnxn
' open Titles table
Set rstTitles = New ADODB.Recordset
strSQLTitles = "titles"
rstTitles.Open strSQLTitles, Cnxn, adOpenDynamic, adLockPessimistic, adCmdTable
Cnxn.BeginTrans
' Display connection mode
If Cnxn.Mode = adModeShareExclusive Then
MsgBox "Connection mode is exclusive."
Else
MsgBox "Connection mode is not exclusive."
End If
' Display isolation level
If Cnxn.IsolationLevel = adXactIsolated Then
MsgBox "Transaction is isolated."
Else
MsgBox "Transaction is not isolated."
End If
' Change the type of psychology titles
Do Until rstTitles.EOF
If Trim(rstTitles!Type) = "psychology" Then
rstTitles!Type = "self_help"
rstTitles.Update
End If
rstTitles.MoveNext
Loop
' Print current data in recordset
rstTitles.Requery
Do While Not rstTitles.EOF
Debug.Print rstTitles!Title & " - " & rstTitles!Type
rstTitles.MoveNext
Loop
' clean up
rstTitles.Close
Cnxn.RollbackTrans
Cnxn.Close
Set rstTitles = Nothing
Set Cnxn = Nothing
Exit Sub
ErrorHandler:
' clean up
If Not rstTitles Is Nothing Then
If rstTitles.State = adStateOpen Then rstTitles.Close
End If
Set rstTitles = Nothing
If Not Cnxn Is Nothing Then
If Cnxn.State = adStateOpen Then
Cnxn.RollbackTrans
Cnxn.Close
End If
End If
Set Cnxn = Nothing
If Err <> 0 Then
MsgBox Err.Source & "-->" & Err.Description, , "Error"
End If
End Sub
'EndIsolationLevelVB