# Codex Pass 02 — Database and Models

## Goal

Add SQLAlchemy/Alembic/PostGIS-ready database foundation.

## Must implement

- database session management;
- base model conventions;
- models for Project, Area, Dataset, AnalysisRun, Metric, Export, Job;
- migration scaffold;
- geometry field strategy documented in code comments or docs;
- indexes for FK and future geometry operations;
- tests for model imports.

## Must preserve

- PostGIS as spatial database;
- additive migration approach;
- UUID or chosen ID strategy consistently.

## Must not implement

- destructive migrations;
- live GRB/OSM fetch;
- AI tables beyond V1 scaffold unless already specified.

## Output

Use `docs/M6_FINAL_HANDOFF_TEMPLATE.md`.