hinder same data?

hi everyone,my question is about entering same data to database,i want to hinder i wrote code below,but when i enter same data or new data ,it records ,how can i control to hinder same data?
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cmd_new_click()
rs.addnew
end sub

cmd_save_click()


rs.MoveFirst
Do While Not rs.EOF
If rs.RecordCount <> 0 Then
If Text1.Text = rs.Fields("NAME").Value Then
MsgBox "this name is recorded,enter new name"

rs.CancelBatch

Exit Sub
else

rs!NAME = Text1.Text
--
--
--

rs.UpdateBatch

End If
End If
rs.MoveNext

Loop
end sub