Question

我想创建一个基本上创建发票的表单，但使用其他一些相关数据作为输入或限制;在将项目添加到发票的过程中，我需要减少另一个表中的项目。由于用户一次会输入几个项目，我想在表单加载时发出“START TRANSACTION”，然后在表单更新时执行“COMMIT”。因此，如果他们取消表单，其他相关表（通过子表单显示）将回滚到以前的值。

Answer 1

无法使用绑定表单完成。您可以使用临时表来存储数据，然后更新主表。有点像kludge，但我过去已经做过了。

请参阅TempTables.MDB page at my website，其中说明了如何在您的应用中使用临时MDB。

Answer 2

是的，可以这样做，以您需要使用此代码的形式控制交易：

Private Sub Form_Open(Cancel As Integer)
    Set Me.Recordset = CurrentDb.OpenRecordset("NAME_OF_YOUR_TABLE_OR_QUERY")
End Sub

之后，您可以使用DBEngine来控制交易。

它对我有用（我正在使用Access 2007）

注意：如果使用表单界面插入新记录，则在引发Form_AfterInsert事件时可以看到它，因此您可以在该事件中使用DbEngine.Rollback来撤消更改。

Answer 3

我已经认识到它可以在绑定表格上使用它。在任何父控件的更改事件上分配包含ID号的变量所需的一切。您需要将该ID值传输到子窗体连接字段，并在主窗体和子窗体两种形式上执行事务。这是我如何做到的例子。

Primary Form VBA

Option Compare Database
Option Explicit

Private boolFrmDirty As Boolean
Private boolFrmSaved As Boolean

Private Sub EmpolyeesID_Change()
Dim ordID As Integer
Dim subFormOrdID As Object

Set subFormOrdID = Forms!Order.OrderInstallation.Form!OrderID

ordID = Me.Form!OrderID

subFormOrdID.DefaultValue = ordID

End Sub

Private Sub Form_AfterDelConfirm(Status As Integer)
    If Me.Saved = False Then Me.Saved = (Status = acDeleteOK)
End Sub
Private Sub Form_AfterUpdate()
    Me.Saved = True
End Sub
Private Sub Form_Delete(Cancel As Integer)
    If Me.Dirtied = False Then DBEngine.BeginTrans
    Me.Dirtied = True
End Sub
'Check if form has got new values in it
Private Sub Form_Dirty(Cancel As Integer)
    If Me.Dirtied = False Then DBEngine.BeginTrans
    Me.Dirtied = True
End Sub
'Open Form as a Record Set and set the variables for it
Private Sub Form_Open(Cancel As Integer)
    Dim db As DAO.Database
    Dim rs As DAO.Recordset
    Set db = CurrentDb
    Set rs = db.OpenRecordset("SELECT * FROM Orders", dbOpenDynaset, dbAppendOnly)
    Set Me.Recordset = rs
End Sub
Private Sub Form_Unload(Cancel As Integer)
    Dim msg As Integer
    If Me.Saved Then
        msg = MsgBox("Do you want to commit all changes?", vbYesNoCancel)
        Select Case msg
            Case vbYes
                DBEngine.CommitTrans
            Case vbNo
                DBEngine.Rollback
            Case vbCancel
                Cancel = True
        End Select
    Else
        If Me.Dirtied Then DBEngine.Rollback
    End If
End Sub

Public Property Get Dirtied() As Boolean
    Dirtied = boolFrmDirty
End Property

Public Property Let Dirtied(boolFrmDirtyIn As Boolean)
    boolFrmDirty = boolFrmDirtyIn
End Property

Public Property Get Saved() As Boolean
    Saved = boolFrmSaved
End Property

Public Property Let Saved(boolFrmSavedIn As Boolean)
    boolFrmSaved = boolFrmSavedIn
End Property

Private Sub ProductID_AfterUpdate()
'Calculations of VAT and Floor Price
Dim clcVAT As Integer
Dim sqlQry As String
Dim instID As Integer

instID = Me.Form!ProductID.Value

sqlQry = "SELECT Products.Price FROM Products WHERE Products.ProductID =" & instID & ""

Me.flPrice.RowSource = sqlQry

End Sub

Sub Form VBA 

Option Compare Database
Option Explicit
'Transaction for sub-form
Private Sub Form_Open(Cancel As Integer)
    Dim db As DAO.Database
    Dim rs As DAO.Recordset
    Set db = CurrentDb
    Set rs = db.OpenRecordset("SELECT * FROM OrderInstallation")
    Set Me.Recordset = rs
End Sub
Private Sub Form_AfterUpdate()
    Dim emplID As Object
    Dim cstmID As Object
    Dim prdcID As Object
    Dim DataArray As Variant
    Dim RqrdFieldErorr As String
    Dim qry As String

    Set emplID = Me.Parent!EmpolyeesID
    Set cstmID = Me.Parent!CustomerID
    Set prdcID = Me.Parent!ProductID

    If IsNull(emplID.Value) Or IsNull(cstmID.Value) Or IsNull(prdcID.Value) Then
        MsgBox ("Please enter select required fields first")

        Else
    End If
End Sub
'Restrict updates of Installation subform if Employee, Customer and Product is not selected
Private Sub InstallationID_AfterUpdate()
    Dim instID As Integer
    Dim instPrice As Integer
    Dim strQry As String

    ' Create query based on InstallationID value
    instID = InstallationID.Value
    strQry = "SELECT Installation.Price, Installation.InstallationID FROM Installation WHERE Installation.InstallationID =" & instID & ""
    Me.Price.RowSource = strQry
End Sub

我可以用事务包装Access表单吗？

3 个答案: