A polymorphic relationship allows one model to belong to more than one other model type through the same association. For example, an Image may belong to either a Post or a User while storing an imageable_id and imageable_type pair instead of separate post_id and user_id columns.

Eloquent provides morphOne, morphMany, morphTo, morphToMany, and morphedByMany for these patterns. Polymorphic relationships reduce duplicated tables for a genuinely shared concept, but they should be used only when the shared behavior is clear because foreign-key enforcement and reporting can be more complex than with ordinary relationships.