Fetching objects with conditions belonging to children

Friday 03 February 2006 3:23:30 pm

Hi,

I have a class event calendar. The children of this class are events. And each event can have an article and a gallery as children. It looks something like that:

event calendar
  event 1
    article
    gallery
  event 2
    article
  event 3
  event 4
    gallery
  event 5
    article
    gallery

Now I want to list all events having an article or a gallery (e.g. event 3 isn't listed). This can look like this:

  event 1
   -> article  -> gallery
  event 2
   -> article
  event 4
   -> gallery
  event 5
   -> article -> gallery

In order to be efficient and to use the offset/limit functionality (e.g. 10 events per page) I don't like this algortihm:

fetch all events sort by event_date
foreach event {
  fetch childen
  if has(article child) or has(gallery child) {
    echo event name
    fetch children
    foreach child {
      echo child.name
    }
  }
}

Another idea was:

fetch all articles and galleries sort by path
event_ids = array()
foreach object {
  fetch parent_event
  if not in_array(parent_event_id, event_ids) {
    echo event.name
    event_ids[] = parent_event_id
  }

  echo object.name  
}

But also here I'm not able to do offset/limit things. And I can't sort by event_date.

I think, I need an extended_attribute_filter with in my content-list-fetch (fetching all events which have children) and fetching the arcticle and gallery children of the retrieved events (cf the first algorithm). Any other ideas?

Thomas