选择随机记录并将记录标记为正在使用

Question

因此，以下选择要使用的随机团队。选择后，我会在“已使用”字段中将此团队标记为“已使用”，稍后再进行更新查询。大多数情况下它都有效，但是在运行了几次之后，我开始得到重复的团队，即使它们被标记为 X。

我还缺少什么来完成这项工作？

SQL 语句如下：

SELECT TOP 1 RandomTeams.[Team Name], RandomTeams.Used
FROM RandomTeams
WHERE (((RandomTeams.Used) Is Null))
ORDER BY Rnd(TeamID);

这是我处理更新以将团队标记为已使用的方式，它按预期工作，用 X 标记时我没有问题：

Text214.Text 包含正在使用的团队名称

strTeam = (Chr(34) + Text214.Text + (Chr(34)))

strSQLUpdateTeams = "UPDATE RandomTeams SET Used = 'X' WHERE [Team Name] = " & strTeam

DoCmd.SetWarnings (WarningsOff)
DoCmd.RunSQL strSQLUpdateTeams

Answer 1

作为测试，将以下代码放入模块中，然后执行它，看看会发生什么。顺便说一句，你如何重置[二手]？

    Sub Test_Teams()
    Dim strSQL      As String
    Dim strTeam     As String
    Dim strSQLUpdateTeams   As String
    Dim dbs         As DAO.Database
    Dim rs          As DAO.recordSet

    Set dbs = CurrentDb
    If MsgBox("Do you want to reset all 'Used' flags?", vbYesNo, "Reset?") = vbYes Then
        strSQL = "update RandomTeams set [Used] = null;"
        dbs.Execute strSQL

    End If
MyLoop:
    strSQL = "SELECT TOP 1 RandomTeams.[Team Name], RandomTeams.Used " & _
            "FROM RandomTeams " & _
            "WHERE (((RandomTeams.Used) Is Null)) " & _
            "ORDER BY Rnd(TeamID);"

    Set rs = dbs.OpenRecordset(strSQL)
    If Not rs.EOF Then
        strTeam = rs![Team Name]
        Debug.Print "Found Team: " & strTeam
    Else
        MsgBox "EOF! No more teams."
        rs.Close
        Set rs = Nothing
        dbs.Close
        Set dbs = Nothing
        Exit Sub
    End If
    strTeam = (Chr(34) + rs![Team Name] + (Chr(34)))
    rs.Close
    Set rs = Nothing

    strSQLUpdateTeams = "UPDATE RandomTeams SET [Used] = 'X' WHERE [Team Name] = " & strTeam
    Debug.Print strSQLUpdateTeams
    'DoCmd.SetWarnings (WarningsOff)
    'DoCmd.RunSQL strSQLUpdateTeams
    dbs.Execute strSQLUpdateTeams
    If dbs.RecordsAffected <> 1 Then
        MsgBox "Whoa! Not good! Update failed!"
    End If
    GoTo MyLoop


End Sub