
    rel = case myname[0, 2]
          when "PS"
              "PSlot"
          when "WS"
              "WSlot"
          when "IF"
              "IFace"
          when "HS"
              "HSlot"
          when "PH"
              "PHone"
          else
              raise "illegal slotlink beginning with #{myname[0, 2]}"
          end
    rec = PL.exec("select * from #{rel} where slotname = '#{myname}'", 1)
    return if ! rec
    if rec["slotlink"] == blname
       PL.exec("update #{rel} set slotlink = ''
                    where slotname = '#{myname}'")
    end
