使用 MS Access 下载缓慢

Question

我有一个子程序可以打开 excel，创建到我的 google sheet 的连接，然后使用插入语句将数据添加到我的 Access 数据库。
这有效但速度非常慢（需要 ~30 秒才能获得 6 条记录）

Private Sub ImportFromGoogleSheet()
On Error GoTo ErrHandler

Dim appXL As Object 'Excel.Application
Dim wbk As Object 'Excel.Workbook
Dim wst As Object 'Excel.Worksheet
Dim Timer As Integer

Set appXL = CreateObject("Excel.Application")
appXL.Visible = True 'If you want to see the excel sheet - enable this row (good for debugging)
Set wbk = appXL.Workbooks.Add
Set wst = wbk.Worksheets(1)

With wst
    .QueryTables.Add Connection:= _
    "URL;https://connection to site here ", Destination:=.Range("$A")
    .Name = "Worksheet1"

    .QueryTables(1).Refresh
End With

'Wait for google-doc data to be downloaded.
Timer = 0
Do While Left(wst.cells(1, 1), 12) = "ExternalData" And Timer < 40
    'Sleep 250 ' Wait 0.25 sec before re-checking data
    'Timer = Timer + 1
Loop

Dim rownum As Integer
rownum = 4
wst.cells(rownum, 2).Select
Do While (wst.cells(rownum, 2).Value <> "")
    Dim sqlStr As String
    Dim ts, dol As Date
    Dim sn, lt As String
    Dim nod As Integer
    ts = wst.cells(rownum, 2).Value
    dol = wst.cells(rownum, 5).Value
    sn = wst.cells(rownum, 3).Value
    lt = wst.cells(rownum, 4).Value
    nod = wst.cells(rownum, 6).Value

    sqlStr = "INSERT INTO table VALUES"
    DoCmd.SetWarnings False
    DoCmd.RunSQL sqlStr
    DoCmd.SetWarnings True

    rownum = rownum + 1
Loop

wbk.Close SaveChanges:=False 'Don't save excel sheet
appXL.Quit
Exit Sub

ErrHandler:
If (Err.Number = 3022) Then
    Debug.Print "Record Already Exists"
    Resume
End If
Debug.Print Err.Description & Err.Number

wbk.Close SaveChanges:=False 'Don't save excel sheet
appXL.Quit
End Sub

我已经尝试删除第一个 while 循环，但随后没有导入任何内容

代码中是否有某些东西减慢了它的速度，或者这只是一个缓慢的过程？

*我知道这可能适合代码审查，但我更感兴趣的是为什么它慢而不是它的错误代码

**编辑以添加调试输出和新的 while

Debug.Print "before wait while " & Now
'Wait for google-doc data to be downloaded.
lTimer = 0
Do While Left(wst.cells(1, 1), 12) = "ExternalData" And lTimer < 40
    Debug.Print "Wait loop " & lTimer 
    Debug.Print "during wait while " & Now
    Sleep 250 ' Wait 0.25 sec before re-checking data
    DoEvents
    lTimer = lTimer + 1
Loop

Debug.Print "after wait while" & Now

代码结束

start time 18/07/2017 9:06:58 a.m.
before connect 18/07/2017 9:06:58 a.m.
before wait while 18/07/2017 9:07:00 a.m.
Wait loop 0
during wait while 18/07/2017 9:07:00 a.m.
Wait loop 1
during wait while 18/07/2017 9:07:00 a.m.
Wait loop 2
during wait while 18/07/2017 9:07:01 a.m.
Wait loop 3
during wait while 18/07/2017 9:07:01 a.m.
Wait loop 4
during wait while 18/07/2017 9:07:01 a.m.
Wait loop 5
during wait while 18/07/2017 9:07:01 a.m.
Wait loop 6
during wait while 18/07/2017 9:07:02 a.m.
Wait loop 7
during wait while 18/07/2017 9:07:02 a.m.
Wait loop 8
during wait while 18/07/2017 9:07:02 a.m.
Wait loop 9
during wait while 18/07/2017 9:07:02 a.m.
Wait loop 10
during wait while 18/07/2017 9:07:03 a.m.
Wait loop 11
during wait while 18/07/2017 9:07:03 a.m.
after wait while 18/07/2017 9:07:28 a.m.

Answer 1

使用Debug.Print查看哪些部分实际花费了这么长时间。 How to debug VBA code

Timer是Access中的函数，请勿将其用作变量名。

您的等待循环必须有一个 Sleep 调用和一个 DoEvents 调用以避免占用您的 CPU。

Private Declare Sub Sleep Lib "kernel32" Alias "Sleep" (ByVal dwMilliseconds As Long)

'Wait for google-doc data to be downloaded.
lTimer = 0
Do While Left(wst.cells(1, 1), 12) = "ExternalData" And lTimer < 40
    Debug.Print "Wait loop " & lTimer    ' Ctrl+g shows output
    Sleep 250 ' Wait 0.25 sec before re-checking data
    DoEvents
    lTimer = lTimer + 1
Loop

如果这没有帮助，您可能不得不忍受它。

Answer 2

发现另一个问题，即仅下载了 100 条记录，该问题的解决方案也解决了速度问题。

我找到了解决方案 here。

它说您需要将 link 的格式从
更改为 https://docs.google.com/spreadsheets/d/YOURSPREADSHEET/edit?usp=sharing
至
https://spreadsheets.google.com/tq?tqx=out:html&tq=&key=YOURSPREADSHEET&gid=1

将其从可编辑视图更改为更基本的视图

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