Database Schema
===============

GCMS uses PostgreSQL as its primary data store, hosted on Supabase.
This section documents the data model that underpins every feature
in the application.

.. toctree::
   :maxdepth: 1

   entity-reference
   er-diagram

Overview
--------

The schema is centred around three core entities:

- **users** — individual people who can sign in to GCMS
- **projects** — group coursework projects that users belong to
- **tasks** — units of work within a project, assigned to users

These are connected by a many-to-many relationship table (``user_projects``)
and supported by feature-specific tables for messages, meetings,
notifications, the interactive project board (``widgets``), shared
project files (``files``), and AI assistant chat history
(``ai_chat_messages``).

All tables use UUID primary keys generated by ``gen_random_uuid()``,
which makes IDs unguessable and avoids the need for sequence
synchronisation across environments.