Postgres gets support for upsert(git.postgresql.org)

    READU REC FROM FILE,KEY ELSE
        REC<1> = 'stuff'
        * Set other fields as appropriate for a brand new record - this is the 'insert'
    END
    REC<1> = 'blah'
    * Set other fields as appropriate for an update
    WRITE BLAH TO FILE,KEY ;* Write record and release locks

  CREATE OR REPLACE RULE "replace_row" AS
  ON INSERT TO my_table
  WHERE EXISTS(SELECT 1 FROM my_table WHERE id=NEW.id)
  DO INSTEAD
  (UPDATE my_table SET
  col1=NEW.col1,
  col2=NEW.col2,
  col3=NEW.col3,
  WHERE id=NEW.id);