[英]MS Access concurrent users
我只是有一個關於 MS Access Concurrency 的快速問題。 我在 excel 中構建了一個輸入表,VB 代碼在大約 5 毫秒內打開與 MS Access 數據庫的連接,記錄 8 個字段並立即關閉連接(對於該特定用戶)。 我意識到 Access 在並發方面有其局限性,但我真的想知道這對於 70 個用戶是否合適? 並非所有人都會在完全相同的時間記錄數據,如果發生這種情況,我想說 70 個(最多)中的 20-30 個可能會在完全相同的時間記錄某些內容。
另一方面,Access 數據庫僅用於存儲數據,僅用於存儲數據。
Dim NewCon As ADODB.Connection
Set NewCon = New ADODB.Connection
Dim Recordset As ADODB.Recordset
Set Recordset = New ADODB.Recordset
NewCon.Open "Provider=Microsoft.ace.oledb.12.0;Data Source=C:\Users\my.user\Desktop\Testing\Database1.accdb"
Recordset.Open "DATA", NewCon, adOpenDynamic, adLockOptimistic
Recordset.AddNew
'Primary Key
Recordset.Fields(0).Value = G
'Field 2
Recordset.Fields(1).Value = A
'Field 3
Recordset.Fields(2).Value = B
'Field 4
Recordset.Fields(3).Value = C
'Field 5
Recordset.Fields(4).Value = D
'Field 6
Recordset.Fields(5).Value = E
'Field 7
Recordset.Fields(6).Value = F
'Field 8
Recordset.Fields(7).Value = Format(Now, "m/d/yyyy h:mm:ss")
Recordset.Update
Recordset.Close
NewCon.Close
這應該不是問題。 或者捕獲錯誤並重試。
如果遇到嚴重問題,可以使用此處描述的方法:
其中包括完整的演示和代碼:
' Function to replace the Edit method of a DAO.Recordset.
' To be used followed by GetUpdate to automatically handle
' concurrent updates.
'
' 2016-02-06. Gustav Brock, Cactus Data ApS, CPH.
'
Public Sub SetEdit(ByRef rs As DAO.Recordset)
On Error GoTo Err_SetEdit
' Attempt to set rs into edit mode.
Do While rs.EditMode <> dbEditInProgress
rs.Edit
If rs.EditMode = dbEditInProgress Then
' rs is ready for edit.
Exit Do
End If
Loop
Exit_SetEdit:
Exit Sub
Err_SetEdit:
If DebugMode Then Debug.Print " Edit", Timer, Err.Description
If Err.Number = 3197 Then
' Concurrent edit.
' Continue in the loop.
' Will normally happen ONCE only for each call of SetEdit.
Resume Next
Else
' Other error, like deleted record.
' Pass error handling to the calling procedure.
Resume Exit_SetEdit
End If
End Sub
和:
' Function to replace the Update method of a DAO.Recordset.
' To be used following SetEdit to automatically handle
' concurrent updates.
'
' 2016-01-31. Gustav Brock, Cactus Data ApS, CPH.
'
Public Function GetUpdate(ByRef rs As DAO.Recordset) As Boolean
On Error GoTo Err_GetUpdate
' Attempt to update rs and terminate edit mode.
rs.Update
GetUpdate = True
Exit_GetUpdate:
Exit Function
Err_GetUpdate:
If DebugMode Then Debug.Print " Update", Timer, Err.Description
' Update failed.
' Cancel and return False.
rs.CancelUpdate
Resume Exit_GetUpdate
End Function
同樣在GitHub
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