自定义函数判断表中某个字段是否有重复值

时　间:2014-07-18 14:31:03
作　者:善解人衣   ID：29924  城市：文山
摘　要:自定义函数判断表中某个字段是否有重复值
正　文:

在模块中自定义函数:ExistDuplicateRecords(Expr As String, Domain As String) As Boolean

调用时第一个参数是要查重复值的字段名,第二个参数是表或查询名称。有重复值时返回True。

以下是第一版本的代码:

'检查一个表中某个字段是否有重复值
Public Function ExistDuplicateRecords(Expr As String, Domain As String) As Boolean
    On Error Resume Next
    Dim strQueryName As String
    Dim strSQL As String
    Dim QDf As QueryDef

    strQueryName = "~重复值查询"
    strSQL = "Select * FROM " & Domain & _
             " Where " & Expr & _
             " In (Select " & Expr & _
             " From  " & Domain & _
             " Group By " & Expr & _
             " Having Count(*)>1)"
    Set QDf = CurrentDb.CreateQueryDef(strQueryName, strSQL)
    If DCount(Expr, strQueryName) > 0 Then
        ExistDuplicateRecords = True
    End If 

'DoCmd.DeleteObject acQuery,strQueryName

 End Function

上面的代码中生成了一个临时的查询，效率不高而且程序文件容易增肥，今天本人又做了修改，新版本代码地址在：http://www.accessoft.com/blog/article-show.asp?userid=29924&Id=9522