Datamapper DataMapper

Let's assume there are an Article model and an Image model. The Article model would need a way to alias an Image in a one_to_one relation as a "Thumbnail".

Right now, as per dkubb on #datamapper, one has to write it like this:

Article.belongs_to :thumbnail, :class_name => 'Image', :child_key => [ :thumbnail_id ]

This, to my feeble mind ;o), makes little sense (hard to figure out), since my thinking is that the Article has One Thumbnail that is actually an Image – instead of the Article belonging to a Thumbnail. A syntax suggested by dkubb, which I think would be easier to understand, would be

Article.has 1, :thumbnail, :via => :image

or an alternative

Article.has 1, :thumbnail, :is => :image

Which would just define a "thumbnail" field in the Articles table and place a reference to the correct Image to use when an Image is assigned as an Article.thumbnail.

This is something that took me some time to get right, since I was "thinking wrong" - in terms of "has" instead of "belongs to".

Thanks for listening ;o)

smoofles