主题：[求助] 防止重复记录

你好，以下代码中可不可以帮忙加一个条件，如果表PrintHistory已经存在相同的PartNo，就不再新增该记录。谢谢。

Dim t1 As Table = Tables("生产任务单")
Dim nmb() As String = {"生产任务单号","产品名称","数量","PrintTime"}
Dim nma() As String = {"生产任务单号","PartNo","Qty","PrintTime"}

For r As Integer = t1.TopPosition To t1.BottomPosition
    Dim dr As Row = Tables("PrintHistory").AddNew
    For i As Integer = 0 To nma.Length - 1
        dr(nma(i)) = t1.rows(r)(nmb(i))
    Next
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