判断与现有记录的编号是否重复的代码怎么写？

下面绿色*号间的代码怎么写？（判断与现在记录的编号是否重复）

Private Sub bt1_Click()
    Dim ADOcn As New ADODB.Connection
    Dim ADOrs As New ADODB.Recordset
    Dim strDB As String
   
    '建立连接
    Set ADOcn = CurrentProject.Connection

    ADOrs.ActiveConnection = ADOcn
    ADOrs.Open "Select 编号 From tEmp Where 编号='" + tNo + "'", , adOpenForwardOnly, adLockReadOnly
    '*****Add1*****
   
    '*****Add1*****
        MsgBox "该编号已存在，不能追加！"
    Else
        strSQL = "Insert Into tEmp (编号,姓名,性别,年龄)"
        strSQL = strSQL + "Values('" + tNo + "','" + tName + "','" + tSex + "'," + tAge + ")"
        ADOcn.Execute strSQL
        MsgBox "添加成功，请继续！"
    End If

    ADOrs.Close
    ADOcn.Close
    Set ADOrs = Nothing
    Set ADOcn = Nothing

End Sub