What is the de-facto/simplest way of deleting a single join entry via the parent?
I was hoping to use a changeset, to add a no assoc constraint on a different association, so deleting a tag for example can only happen when there are no associated comments. But I’m coming a little unstuck.
def remove_tag(post, tag) do
post
|> change
|> no_assoc_constraint(:comments)
|> put_assoc(:tags, #?????)
|> Repo.update
end