This relationship is a variation of the InverseForeignKeyReference, that is the "one" in one-to-many,
where the gathered records are presented as a mapping or array. The records are indexed using the values of
a field on the related object.
For example:
A type "user" has a primary key field id. A type "preference" has a foreign key field "user_id" that
indicates the user for which that preference is associated. The definition of the "preference" type
would contain a reference for the foreign key (a Fins.Model.ForeignKeyRelationship ) whereas the
"user" object definition would contain the inverse relationship (Fins.Model.InverseForeignKeyRelationship )
which could be used to find all "preference" objects owned by that user.
This type of reference adds a twist to this idea: if the "preference" object had some field that identified the
particular preference for this user, perhaps "preference_name", we could use this (MappedForeignKeyReference )
relationship type to organize the user's preferences in a mapping by name, saving us from having to perform an
additional find operation:
someuser["preferences"]["default_folder"]
Fins.Model.LikeCriteria()->get()