CREATE OR REPLACE FUNCTION tnrs_populate_accepted_scientific_name()

  RETURNS trigger AS

$BODY$

BEGIN

    new."Accepted_scientific_name" = NULLIF(array_to_string(ARRAY[

        NULLIF(new."Accepted_name_family", 'Unknown')

        , new."Accepted_name"

        , new."Accepted_name_author"

    ], ' '), '');

    RETURN new;

END;

$BODY$

  LANGUAGE plpgsql VOLATILE

  COST 100;

CREATE TRIGGER tnrs_populate_accepted_scientific_name

  BEFORE INSERT OR UPDATE

  ON tnrs

  FOR EACH ROW

  EXECUTE PROCEDURE tnrs_populate_accepted_scientific_name();