如何加快 ADODB 连接

Posted 2023-05-07

【中文标题】如何加快 ADODB 连接

【英文标题】：How Can I Speed Up An ADODB Connection

【发布时间】：2019-03-28 20:39:48

【问题描述】：

我正在运行下面的代码，将 Access 数据库中的数据检索到 Excel 中。代码执行大约需要 1 分钟。目前大约有 8 列的 500 条记录。我可以做些什么来修改我的代码以更快地运行？

Sub sync_Data()
    Application.ScreenUpdating = False
    Application.EnableEvents = False
    Application.Calculation = xlCalculationManual

    Dim cn As ADODB.Connection, rs As ADODB.Recordset
    Dim mysqlSt As String
    Dim rowindex As Long

    mysqlSt = "SELECT pbsclients.client, pbsclients.priority, pbsclients.source, pbsclients.lastcontact, pbsclients.result, pbsclients.nextsteps, pbsclients.attempts, pbsclients.notes FROM pbsclients; "

    Set cn = New ADODB.Connection
    With cn
        .ConnectionString = con1
        .Open
    End With

    rowindex = 2
    Set rs = New ADODB.Recordset
    rs.Open mysqlSt, cn, adOpenDynamic, adLockOptimistic

    While Not rs.EOF
        Sheet3.Cells(rowindex, 1) = rs!client
        Sheet3.Cells(rowindex, 2) = rs!Priority
        Sheet3.Cells(rowindex, 3) = rs!Source
        Sheet3.Cells(rowindex, 4) = rs!lastcontact
        Sheet3.Cells(rowindex, 5) = rs!result
        Sheet3.Cells(rowindex, 6) = rs!nextsteps
        Sheet3.Cells(rowindex, 7) = rs!attempts
        Sheet3.Cells(rowindex, 8) = rs!Notes

        rowindex = rowindex + 1
        rs.MoveNext
    Wend

    rs.Close
    Set rs = Nothing
    cn.Close
    Set cn = Nothing
    Exit Sub

    Application.ScreenUpdating = True
    Application.EnableEvents = True
    Application.Calculation = xlCalculationAutomatic
End Sub

【问题讨论】：

试试Range.CopyFromRecordset。

而不是 While Not rs.EOF 和 Wend 之间的所有内容。

实际上，而不是整个 While...Wend 块。 FWIW While...Wend 是一个过时的构造，应该是 Do While...Loop 以允许 Exit Do 语句。

你需要以某种方式点击索引......尝试WHERE Id <> 0（假设是单列，自动编号PK）

试试看。假设员工是一个文本字段：WHERE ID <> 0 AND employee ='" & sheet3.range("D5") & "'"

【参考方案1】：

这是我的代码的工作版本，运行和检索大约需要 2 秒，而上面的代码需要 45 秒 - 1 分钟。

Sub sync_Data()
    Application.ScreenUpdating = False
Application.EnableEvents = False
Application.Calculation = xlCalculationManual

Dim cn As ADODB.Connection, rs As ADODB.Recordset
Dim mysqlSt As String
Dim rowindex As Long


mysqlSt = "SELECT pbsclients.client, pbsclients.priority, pbsclients.source, pbsclients.lastcontact, pbsclients.result, pbsclients.nextsteps, pbsclients.attempts, pbsclients.notes FROM pbsclients WHERE Id <> 0 AND pbsclients.branch = '" & Sheet3.Range("Z1") & "'"

Set cn = New ADODB.Connection

With cn
    .ConnectionString = con1
    .Open
    End With
    rowindex = 2
    Set rs = New ADODB.Recordset
    rs.Open mysqlSt, cn, adOpenDynamic, adLockOptimistic

    Do While Not rs.EOF

    Sheet3.Range("A2").CopyFromRecordset rs

    Loop

    rs.Close
      cn.Close
    Set rs = Nothing

    Set cn = Nothing
    Exit Sub
Application.ScreenUpdating = True
Application.EnableEvents = True
Application.Calculation = xlCalculationAutomatic
End Sub

【讨论】：

你可以通过删除.CopyFromRecordset rs周围的Do While Not rs.EOF + Loop来使你的代码更清晰。