Augusts BautraLet's say we have a model structure that allows us to make comments on anything:
Comment.has_one :comment_commentee_tie
CommentCommenteeTie
belongs_to :comment
belongs_to :commentee, polymorphic: true
Post
has_many :comment_commentee_ties
Now let's say we want to filter comments by possible post data. To alleviate the joining, we can define a non-polymorphic association for Comment:
Comment
has_one :comment_commentee_tie
has_one :post, through: :comment_commentee_tie, source: :commentee, source_type: "Post"
Polymorphic children
Let's look at the harder case with has_many :children, polymorphic: true
We can use the scope option to filter what types of children we want:
Parent
has_many :parent_child_ties
has_many(
:good_children,
-> { where(child_type: "GoodChild") },
through: :parent_child_ties,
source: :child,
source_type: "GoodChild"
)
