我收到一些表格,其中有按链接列表分组的元素,但我无法处理它。

该函数可以正常工作,但我经常被问到自任务调度程序启动时它的宏在哪里,或者有一些内存问题。

我使用以下代码找出 idGroup(翻译成英文),我想知道是否有办法改进它,尤其是它的速度,因为 30 000 行和大约 2500 个组最多需要一个小时......(这就是为什么我使用 VBA 来查看进度......)

'Simple example
'idGroup,id2,id1
'6338546,14322882,13608969
'6338546,13608969,13255363
'6338546,6338546,14322882
'6338546,11837926,11316332
'6338546,12297571,11837926
'6338546,13255363,12811071
'6338546,12811071,12297571
'6338546,7610194,7343817
'6338546,7935943,7610194
'6338546,8531387,7935943
'6338546,6944491,6611041
'6338546,7343817,6944491
'6338546,9968746,9632204
'6338546,10381694,9968746
'6338546,6611041,0
'6338546,8920224,8531387
'6338546,9632204,8920224
'6338546,11316332,10941093
'6338546,10941093,10381694


Public Function GetidGroup()
    'first id1 is always 0
    sql = "SELECT idGroup, id2, id1 FROM TABLE_WITH_LINKED_LIST WHERE id1='0' ORDER BY id2 DESC"
    Dim rs As Recordset
    Dim uidLikedList As String, id2 As String, id1 As String

    Set rs = CurrentDb.OpenRecordset(sql)
    Dim total As Long
    Dim idGroup As String
    Dim incrément As Long, progress As Double

    total = rs.RecordCount
    incrément = 1

    While Not rs.EOF
        progress = Math.Round(100 * incrément / total, 2)

        'Print in order to avoir freezing
        Debug.Print progress

        If rs.Fields("idGroup") = "" Then
            id2 = rs.Fields("id2")

            idGroup = precedentUid(id2)

            rs.Edit
            rs.Fields("idGroup") = idGroup
            rs.Update
        End If

        incrément = incrément + 1
        rs.MoveNext
    Wend

    rs.Close
    Set rs = Nothing
    GetidGroup = total
End Function

'Recursive function
'Deepest so far is about 62 calls
Public Function precedentUid(id2 As String) As String
    sql = "SELECT idGroup, id2 FROM TABLE_WITH_LINKED_LIST WHERE id1 = '" & id2 & "'"
    Dim rs As Recordset
    Dim precedentid2 As String
    Dim idGroup As String
    Dim ret As String

    Set rs = CurrentDb.OpenRecordset(sql)
    If rs.EOF Then
        rs.Close
        Set rs = Nothing
        precedentUid = id2
    Else
        'Some records have several references
        '56 impacted records  :
        'TODO : Give the min id2 to the group
        ret = "-1"
        While Not rs.EOF
            If rs.Fields("idGroup") = "" Then
                precedentid2 = rs.Fields("id2")
                idGroup = precedentUid(precedentid2)

                If ret = "-1" Or CLng(ret) > CLng(idGroup) Then
                    ret = idGroup
                End If

                'Debug.Print id2 & " " & precedentid2 & " " & idGroup

                rs.Edit
                    rs.Fields("idGroup") = idGroup
                rs.Update
            End If
            rs.MoveNext
        Wend
        rs.Close
        Set rs = Nothing
        precedentUid = ret
    End If
End Function

最佳答案

一些建议:

  • 您正在打开大量记录集(每次调用 precedentUid 时)。相反,请考虑使用按 idGroup + id1 排序的单个记录集并向上或向下查找适当的值。
  • 由于您一直在搜索 idGroup + id1 ,我建议将其设为主键。然后,您将能够使用 Seek 方法进行更快的搜索。
  • 一旦有了主键,就不需要可编辑单个记录集,而且加载速度会更快。当您必须更新 idGroup 时,请将 SQL 语句与 CurrentDb.Execute 一起使用。
  • idGroup 中缓存搜索 Dictionary 的结果(引用 Microsoft Scripting Runtime 工具 -> References )。这样,您就不会在递归时重复搜索。
  • 您的示例数据似乎都是数字,但您正在从记录集中检索它们作为字符串。基础数据类型应该是 Long ,而不是 Text 。如果您对此没有控制权,我会考虑创建一个具有适当数据类型的临时表。
  • 关于sql - Access 2007 改进查询/vba 以按链接列表分组,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/12728248/

    10-09 20:59