# Milestone 19: ER Diagram and Documentation

## Objective

Produce final database documentation and ER diagram.

## Backend Deliverables

- Mermaid ER diagram.
- Table-by-table Markdown documentation.
- Relationship documentation.
- Index strategy documentation.
- Foreign key documentation.

## Completion Criteria

- Database documentation matches Prisma schema.
- ER diagram covers all core tables.
- Documentation can be used by backend, frontend, and reporting work.

## Implementation Notes

- ER documentation is available in `backend/docs/er-diagram.md`.
- The Mermaid diagram covers authentication, RBAC, project delivery, task collaboration, reporting, costing, notifications, jobs, audit, and calendar availability.
- Index and foreign key strategy are documented for backend and reporting work.