Question

美好的一天，
我的问题是如何处理异常或摆脱与＃34相关的错误;无法打开更多的表＆＃34;。为了概述我正在创建的程序，我在ms access 2007中提取了主题记录，我循环到该记录以随机分配一个时间表并逐个插入表中指定时间表的新记录。

我的程序流程只插入记录工作一定次数，就像差不多200次，并且在某些时候停止并弹出oledbexception

提前感谢您回答我的问题。

这是我的代码，用于更详细地了解我的程序，

Private Sub Assignsched(ByVal rType As String, ByVal subjectCode As String, ByVal SecID As String, ByVal CourseCode As String)
    If shrdcon.con.State = ConnectionState.Closed Then
        shrdcon.con.Open()
    End If
    Dim RoomNum As Integer
    dtARoom.Clear()
    Dim stoploop As Boolean

    Dim count As Integer = 0

    Dim rm1 As String
    RoomAssign = ""
    rm1 = "SELECT * FROM tblRoom WHERE RoomType = '" & rType & "'"
    Dim dat As New OleDbDataAdapter(rm1, shrdcon.con)
    dat.Fill(ds, "ARoom")




        stoploop = False
        count = 0
        Do Until stoploop = "True"
        RoomNum = rndm.Next(0, ds.Tables("ARoom").Rows.Count)
        RoomAssign = ds.Tables("ARoom").Rows(RoomNum).Item(1)

            ScheduleGeneration()

        If checkExisting(sTime, eTime, RoomAssign, daypick) = False Then


            RoomA = RoomAssign

            GenerateOfferingID()
            Dim cmd1 As New OleDbCommand()
            cmd1.CommandText = "INSERT INTO [tblSubjectOffer]([SubjectOID],[SubjectCode],[SectionID],[Day],[sTime],[eTime],[RoomName],[CourseCode]) VALUES('" & _
                                myId & "','" & subjectCode & "','" & SecID & "','" & daypick & "'," & sTime & "," & eTime & ",'" & RoomA & "','" & CourseCode & "')"
            cmd1.Connection = shrdcon.con
            cmd1.ExecuteNonQuery()
            cmd1.Dispose()

            Dim pipz As New OleDbCommand("Update tblGenerator Set NextNo='" & myId & "' where TableName ='" & "tblSubjectOffer" & "'", shrdcon.con)
            pipz.ExecuteNonQuery()
            pipz.Dispose()
            stoploop = True
        Else
            stoploop = False
        End If
            If stoploop = False Then

            If count = 30 Then
                stoploop = True
            Else

                count = count + 1

            End If
            End If
        Loop
End Sub

Answer 1

当您超过Microsoft Jet数据库引擎允许的最大打开TableID数时，Microsoft Jet引擎会发生这种典型错误，其中Jet3.5引擎为2048，旧引擎为1024。

即使您在每次使用后关闭Command对象，您仍然在整个过程中使用相同的连接，这实际上保存了TableID，并且在某个时间点超过了允许打开的TableID的数量＃39; S

一个可能的解决方案是使用最新版本here

更新Jet引擎

它可能会解决您的问题，但如果您已经在使用最新的引擎，则必须查看其他选项以减少数据库操作的数量。

尝试使用UpdateBatch方法批量应用更新。

希望这有帮助

Private Sub Command1_Click()

    Dim myConnection As ADODB.Connection
    Dim rsData As ADODB.Recordset

    Set myConnection = New ADODB.Connection
    myConnection.ConnectionString = "xxxxxxxxxxxxxxxxxxxx"
    myConnection.Open

    Set rsData = New ADODB.Recordset
    rsData.CursorLocation = adUseClient
    rsData.Open "select * from mytable", myConnection, adOpenStatic, adLockBatchOptimistic

    For i = 1 To 10000
        rsData.AddNew
        rsData.Fields(0).Value = 1
        rsData.Fields(1).Value = 2
    Next i

    rsData.UpdateBatch

    rsData.Close
    myConnection.Close
    Set rsData = Nothing
End Sub

Answer 2

晚上好，最近我遇到这种类型的错误，我能够通过添加来解决它 con.close并在任何insert / update或select语句之前调用conState（下面的过程conState-检查）在我的代码中我有类似

的东西

For i = 0 To DataGridView1.RowCount - 1


            reg = DataGridView1.Rows(i).Cells(0).Value
            Label2.Text = reg

'i added this two lines
            ***con.Close()***
            ***Call conState()***

            Dim cmdcheck As New OleDbCommand("Select * from [2015/2016 UG CRF] where regno ='" & reg & "'", con)
            Dim drcheck As OleDbDataReader
            drcheck = cmdcheck.ExecuteReader
            If drcheck.Read = True Then

                GoTo A

            End If

            coursesFirst = String.Empty
            coursesSecond = String.Empty
            creditFirst = 0
            creditSecond = 0
            Dim cmdlevel As New OleDbCommand("Select * from [2015/2016 UG registration Biodata 5 april 16] where regno ='" & reg & "'", con)
            Dim drlevel As OleDbDataReader
            drlevel = cmdlevel.ExecuteReader

            If drlevel.Read = True Then
                level = drlevel.Item("level").ToString
                faculty = drlevel.Item("faculty").ToString
                program = drlevel.Item("programme").ToString

            End If

...............

next

conState是连接测试，如果连接已关闭，则应再次打开它，如下面的

Public Sub conState()
        If con.State = ConnectionState.Closed Then
            con.Open()

        End If

    End Sub

这会停止错误消息

Answer 3

我在C＃应用程序中遇到此异常，原因是使用了OleDbDataReader实例而没有关闭它们：

OleDbDataReader reader = cmd.ExecuteReader();
bool result = reader.Read();
reader.Close(); // <= Problem went away after adding this
return result;

无法再打开表 - OleDbException未处理

3 个答案: