# Pass 03 — Database and Domain Foundation

## Goal

Add the PostGIS-ready database/domain foundation.

## Implement

- SQLAlchemy database setup.
- Alembic migration setup.
- Core models: Project, Area, Dataset, AnalysisRun, Export.
- Pydantic schemas matching API contract style.
- Geometry handling strategy ready for PostGIS.

## Constraints

- Do not store geometry as arbitrary strings in final domain models.
- If test environment cannot run PostGIS, isolate integration tests and keep unit tests safe.
- Do not remove future raster/AI fields because V1 starts smaller.

## Validation

- Backend imports.
- Model metadata initializes.
- Migration command documented or executed if environment allows.
- Unit tests pass.

## Acceptance

- Domain model can support project -> area -> dataset -> analysis.
- Geometry metadata and CRS are represented.
- Execution log updated.