Design Airbnb database

Start by clarifying the exact contract for Airbnb Database: input representation, mutation rules, duplicate behavior, and what should happen on invalid or empty input. The core idea is transactional booking model that prevents overlapping stays. Work a tiny example aloud and name the invariant after each step, because that is the proof that the approach stays correct as the input grows.

A dependable implementation plan is to model listings users reservations payments and reviews; use half-open dates; index listing-date queries; enforce overlap prevention in authoritative transaction. A read-then-insert availability check races under concurrency. Keep the code aligned with that invariant instead of adding special cases that silently change the contract. Test the smallest input, a normal case, duplicates or ties where relevant, an adversarial boundary, and a case that exercises the failure path. The expected complexity is indexed lookups are O(log n) in typical relational indexes. Explain both time and auxiliary memory, including recursion or helper structures; do not hide sorting, copying, or repeated scans. If the title omits critical constraints, say what you need to know before committing to a more specialized solution.