Triggers and database functions

A trigger can stamp updated_at on every edit, write an audit row, or create follow-up records when an order arrives. A database function bundles several steps, such as checking and reducing stock, into one call that runs as a single transaction, which avoids race conditions between two buyers.

In PostgreSQL these are usually written in SQL or PL/pgSQL, and Supabase exposes functions to apps as RPC calls. Logic that lives in the database is powerful but easy to forget, so it belongs in migrations and deserves documentation.