[Deprecated] DMZ 1.5.4 (DataMapper OverZealous Edition)

[eluser]OverZealous[/eluser]
@BrianDHall

Yes, you can mix relationships, even as you mentioned. Of course, you'll need a dedicated column to track the default image, and you'll also need to save that image twice (once with all images, and once as the default). It's just two different relationships to the same image, as far as DMZ is concerned. Note that if the primary image is deleted or un-related, then there will be no primary image defined.

If you go with this (which is simple enough), I would add a "primary_image_id" ITFK column to your listings table (or you'll need to add a column of the same name to your join table).

Alternatively, you can add a isprimary column to your join table (if you have one), and use Join Fields, which are perfect for this sort of thing.

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On an unrelated note, I tried to implement an include_related_count method, and it just isn't feasible within DMZ. The reason is that the group by clause needs to have every single non-aggregated column listed, or the query fails (in my tests). This became too complicated for a limited-use feature. Sorry!