Question

Dim mydb As DAO.Database
Dim myrst As DAO.Recordset
Dim Date1, Date2 As Date
Dim mysql As String
Dim qdf As QueryDef
Dim EmployeeID As String

    EmployeeID = DLookup("lngEmpID", "tblEmployees", "Forms!frmEmployeeOrderForm.cboEmployeeName.Value = EmployeeName")
    Me.EmpID = EmployeeID
    PickupTime = DLookup("Pickup", "tblEmployees", "Forms!frmEmployeeOrderForm.cboEmployeeName.Value = EmployeeName")
    Me.PickupDay = PickupTime

    Set mydb = CurrentDb
    Date1 = Me.dtmGiveAwayDate1
    Date2 = Me.dtmGiveAwayDate2
    mysql = ("Select tblOrders.lngEmpID, tblOrders.dtmGiveAwayDate1, tblOrders.dtmGiveAwayDate2 FROM tblOrders WHERE tblOrders.lngEmpID =" & EmployeeID & " AND tblOrders.dtmGiveAwayDate1 =" & Date1 & " AND tblOrders.dtmGiveAwayDate2 =" & Date2)
    MsgBox mysql
    Set myrst = mydb.OpenRecordset(mysql)

    If myrst.EOF = False Then
        MsgBox "You have already ordered for this PFG." & vbCrLf & "Please see Jody for help."
        cmdCancel_Click
        Exit Sub
    End If

当我运行该程序时，我试图阻止员工在相同日期两次输入他们的名字。为了测试，我尝试复制同一员工的记录，并且不会触发myrst.eof = false并显示消息框，其中显示＆＃34;您已订购此PFG＆＃34;。任何帮助深表感谢。

提前谢谢。

Answer 1

使用FindFirst方法：

myrst.FindFirst "field = " & value

If myrst.NoMatch Then
      //code when record doesn't exist       
End If

Answer 2

检查与日期的相等性可能很棘手。由于VBA日期可以包括纳秒的时间，可能是一方（SQL /代码）有实时，而另一方有默认的午夜值？

Answer 3

    Set mydb = CurrentDb
    Date1 = Format(Me.dtmGiveAwayDate1, "Short Date")
    Date2 = Format(Me.dtmGiveAwayDate2, "Short Date")
    mysql = ("Select tblOrders.lngEmpID, tblOrders.dtmGiveAwayDate1, tblOrders.dtmGiveAwayDate2 FROM tblOrders WHERE tblOrders.lngEmpID =" & EmployeeID & " AND tblOrders.dtmGiveAwayDate1 =" & "#" & Date1 & "#" & " AND tblOrders.dtmGiveAwayDate2 =" & "#" & Date2 & "#")
    MsgBox mysql
    Set myrst = mydb.OpenRecordset(mysql)

这是我使用的代码，现在可以使用了。谢谢。

你如何找到记录是否存在？

3 个答案: