I have the following set of Models / Associations:
Whilst this makes sense from on object oriented point of view, it introduces a huge distance between, for example; a NewsItem and the Photo.image that represents it in the UI.
An obvious improvement would be to dispense with MediaItem and make Video and Photo Polymorphic, however I need to treat them interchangeably, ordering, ranking them searching for them, and a Polymorphic association makes this vastly more complex / awkward. It would also involve many duplicated attributes (that are currently on MediaItem).
My main problem with this setup is that I have situations where a NewsItem is visually represented. Along with its title, I display an image which is the cover image of that NewsItem – effectively the first Photo in the gallery.
In this situation I am effectively doing this:
news_item.gallery.media_items.cover_photo.image.url(:thumbnail)
Given that there are up to 20 of these items on the screen at a time (possibly more), I definitely need to make sure I optimise the database queries by awkward chains of includes.
Of course I can go a large way to hiding some of the access behind delegation, for example:
news_item.gallery_cover_image
But this still leaves me with awkward queries trying to include the chain of tables.
Is there a more sensible way of structuring this?