Decrel is a Scala library that provides the Relation datatype. Through that, Decrel lets you treat the (usually implied) relation information between data as first-class values.
The real-world benefit is similar to adopting optics combinators over field accessors. However, its use case is data retrieval from your datasource or value generation in tests instead of getting or setting values on in-memory data structures.
Links
GitHub: https://github.com/yoohaemin/decrel
Documentation: https://decrel.yoohaemin.com