You just have to add e.g.:
def element_changeset(element_photo, attrs) do
element_photo
|> cast(attrs, [:order, :photo_id])
|> cast_assoc(:photo)
|> validate_required([:order])
|> validate_either(:photo_id, :photo)
|> foreign_key_constraint(:element_id)
|> foreign_key_constraint(:photo_id)
end
and change your
cast_assoc(:element_photos)
to
cast_assoc(:element_photos, with: &ElementPhotos.element_changeset/2
and it should work like you want to.
I don’t follow. My Element is definitely using the ElementPhotos changeset already for the cast_assoc, as it’s showing the validate_either message. The problem is the Element (which doesn’t exist yet) isn’t being added to the changeset. I can’t do it, and Ecto isn’t doing it for me.
If you construct it via cast_assoc from an Element, the ElementPhoto doesn’t have an Element in the changeset.
The association is handled during insert / update of the Element and the correct ids for the associations getting set automatically.
Awesome, that got it! I actually ended up not needing to call the changeset explicitly, just cast_assoc(:element_photos) did the trick.
Thank you so much! This really helped me clean up that mess!