ACS3 Data Model

     1: function wp_previous_slide(
     2:   v_sort_key IN wp_slides.sort_key%TYPE,
     3:   v_presentation_id IN wp_slides.presentation_id%TYPE,
     4:   v_checkpoint IN wp_checkpoints.checkpoint%TYPE
     5: )
     6: return integer is
     7:   ret integer;
     8: begin
     9:   if v_checkpoint is null then
    10:     select slide_id into ret
    11:     from   wp_slides
    12:     where  presentation_id = v_presentation_id
    13:     and    max_checkpoint is null
    14:     and    sort_key = (select max(sort_key) from wp_slides
    15:                        where  presentation_id = v_presentation_id
    16:                        and    max_checkpoint is null
    17:                        and    sort_key < v_sort_key);
    18:   else
    19:     select slide_id into ret
    20:     from   wp_historical_sort
    21:     where  presentation_id = v_presentation_id
    22:     and    checkpoint = v_checkpoint
    23:     and    sort_key = (select max(sort_key) from wp_historical_sort
    24:                        where  presentation_id = v_presentation_id
    25:                        and    checkpoint = v_checkpoint
    26:                        and    sort_key < v_sort_key);
    27:   end if;
    28:   return ret;
    29: end;