https://rubystacknews.com/2026/02/13/range-on-rails-how-postgresql-multirange-turned-complex-booking-logic-into-elegant-simplicity/

At Kaigi on Rails 2025, Tomohiro Umeda shared a powerful real-world case study from chocoZAP: building a reservation system without fixed time slots — and making it elegant instead of chaotic.

Instead of complex conditionals, the solution relies on a mathematical model: 👉 Treat availability as operations on time ranges 👉 Use PostgreSQL Multirange to represent fragmented intervals 👉 Push complexity into SQL, keep Rails code clean