text: use NBNData;
  
  begin tran
      
      delete from TAXON_DETERMINATION
      where TAXON_DETERMINATION_KEY NOT IN
      (
          select MIN(taxon_determination_key)
          from TAXON_DETERMINATION txd
          group by
          txd.TAXON_OCCURRENCE_KEY
          ,txd.TAXON_LIST_ITEM_KEY
          ,txd.DETERMINER
          ,txd.DETERMINATION_TYPE_KEY
          ,txd.VAGUE_DATE_START
      ) 
      and PREFERRED != 1 
  
  commit tran