[英]MS Access concurrent users
我只是有一个关于 MS Access Concurrency 的快速问题。 我在 excel 中构建了一个输入表,VB 代码在大约 5 毫秒内打开与 MS Access 数据库的连接,记录 8 个字段并立即关闭连接(对于该特定用户)。 我意识到 Access 在并发方面有其局限性,但我真的想知道这对于 70 个用户是否合适? 并非所有人都会在完全相同的时间记录数据,如果发生这种情况,我想说 70 个(最多)中的 20-30 个可能会在完全相同的时间记录某些内容。
另一方面,Access 数据库仅用于存储数据,仅用于存储数据。
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
这应该不是问题。 或者捕获错误并重试。
如果遇到严重问题,可以使用此处描述的方法:
其中包括完整的演示和代码:
' 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
同样在GitHub
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