如果連接丟失，則使用宏接口

Question

我有一系列指定時運行的代碼，第一種是連接檢查。如果它成功，那麼它允許代碼繼續，如果不是，它會完全停止代碼。然而，我擔心在這個過程之後連接丟失時會發生什麼。在這個過程中，如果連接終止中間下載，那麼在本地表上有數據上傳到我們的SQL服務器，有時數據仍然被傳輸，但如果它立即發生，數據不會傳輸。

代碼的第二部分刪除所有包含員工信息的本地表內容，然後下載新數據，以便在有任何更新時提供最新信息。

我想弄清楚是否有一種方法或代碼可以實現告訴查詢在連接丟失時立即停止運行，或者如果有方法可以在發生連接時將其撤消。

或者將連接代碼與上傳和刪除代碼結合起來，這樣每次啓動流程之前都會運行它是不是一個好主意？

運行之初的連接代碼：

Public Function StartUp() 
Dim cnn As ADODB.Connection 
Dim localrst As New ADODB.Recordset 
Dim remoterst As New ADODB.Recordset 


On Error Resume Next 
Set cnn = New ADODB.Connection 


cnn.Open "Provider=PRO; Data Source=SOURCE; Initial Catalog=CAT;" _ 
& "User Id=ID; Password=PW;" 

If cnn.State = adStateOpen Then 
    MsgBox ("You have an established connection with the L&TD SQL Server Database and the CDData table has been uploaded to the server.") 
Else 
MsgBox ("Cannot connect to SQL Server. Data will be stored locally to CDData Table until application is opened again with an established connection.") 
End 
End If 

On Error GoTo 0 

' MsgBox ("Please wait while the database is updating, this may take a moment.") 

End Function 

正如你所看到的，我把一個結束結束前如果是這樣，如果沒有連接，它只是完全結束。

上傳代碼是

Public Function Update() 
Dim cdb As DAO.Database, qdf As DAO.QueryDef 

Dim rs As DAO.Recordset 

Dim err As DAO.Error 

' Const DestinationTableName = "AC_CDData" 

Const ConnectionString = _ 
     "ODBC;" & _ 
      "Driver={SQL Server Native Client 10.0};" & _ 
      "Server=SERV;" & _ 
      "Database=DB;" & _ 
      "UID=ID;" & _ 
      "PWD=PWD;" 
Set cdb = CurrentDb 
Set qdf = cdb.CreateQueryDef("") 

Set rs = CurrentDb.OpenRecordset("CDData", dbOpenTable) 

qdf.Connect = ConnectionString 

Do While Not rs.EOF 

    qdf.SQL = "INSERT INTO AC_CDData_1(EmployeeID, EmployeeName, Region, District, Function1, Gender, EEOC, Division, Center, MeetingReadinessLevel, ManagerReadinessLevel, EmployeeFeedback, DevelopmentForEmployee1, DevelopmentForEmployee2, DevelopmentForEmployee3, DevelopmentForEmployee4, DevelopmentForEmployee5, Justification, Notes, Changed, JobGroupCode, JobDesc, JobGroup) " & _ 
       "Values (" & _ 
       "'" & rs!EmployeeID & "', " & _ 
       "'" & rs!EmployeeName & "', " & _ 
       "'" & rs!Region & "', " & _ 
       "'" & rs!District & "', " & _ 
       "'" & rs!Function1 & "', " & _ 
       "'" & rs!Gender & "', " & _ 
       "'" & rs!EEOC & "', " & _ 
       "'" & rs!Division & "', " & _ 
       "'" & rs!Center & "', " & _ 
       "'" & rs!ManagerReadinessLevel & "', " & _ 
       "'" & rs!MeetingReadinessLevel & "', " & _ 
       "'" & rs!EmployeeFeedback & "', " & _ 
       "'" & rs!DevelopmentForEmployee1 & "', " & _ 
       "'" & rs!DevelopmentForEmployee2 & "', " & _ 
       "'" & rs!DevelopmentForEmployee3 & "', " & _ 
       "'" & rs!DevelopmentForEmployee4 & "', " & _ 
       "'" & rs!DevelopmentForEmployee5 & "', " & _ 
       "'" & rs!Justification & "', " & _ 
       "'" & rs!Notes & "', " & _ 
       "'" & rs!Changed & "', " & _ 
       "'" & rs!JobGroupCode & "', " & _ 
       "'" & rs!JobDesc & "', " & _ 
       "'" & rs!JobGroup & "')" 


qdf.ReturnsRecords = False 
On Error GoTo Update_qdfError 
qdf.Execute dbFailOnError 
On Error GoTo 0 

rs.MoveNext 
Loop 

rs.Close 

Set qdf = Nothing 
Set cdb = Nothing 
Set rs = Nothing 
Exit Function 

Update_qdfError: 
For Each err In DAO.Errors 
    MsgBox err.Description, vbCritical, "Error " & err.Number 
Next 

End Function 

那麼，有沒有辦法可以修改連接代碼，並將其添加到更新的代碼（減去消息框），因此如果連接切斷它將終止碼？

Answer 1

您是否嘗試過交易？在事務中包裝插入腳本將不會更改數據庫，除非您已明確提交事務。如果在插入過程中數據連接丟失，則不會調用提交，並且SQL Server數據不會被更改。

見http://msdn.microsoft.com/en-us/library/office/ff196400%28v=office.15%29.aspx