Django Patterns

When to use this skill

Use this skill when working on Django apps/APIs and you want safe model design, query performance awareness, and clean view/service structure.

Core patterns

Settings and environments

• keep secrets out of repo
• separate settings for dev/staging/prod
• validate required env vars on startup

Models: constraints + indexes

• use DB constraints for invariants
• add indexes for common filters/joins
• avoid “magic” implicit behavior without tests

Query performance (avoid N+1)

• use select_related / prefetch_related intentionally
• avoid per-row queries in loops

Views: thin, services: thick

• views/DRF viewsets should parse input and return responses
• business logic belongs in services/domain modules

Migrations

• additive first
• backfill safely
• enforce constraints in later migrations

Testing

• unit tests for pure logic
• integration tests for ORM queries and views

Atlarix tool notes

• Explore: locate settings, apps, and urls; map core models and their relations.
• Build: run pytest/manage.py test; keep migrations small and reversible.
• Debug: inspect stack traces; reproduce failing query patterns.
• Review: check query count and migration safety.

Common mistakes to avoid

• N+1 queries hidden in serializers/templates
• Fat models with unrelated responsibilities
• Unsafe migrations on large tables

Mini-checklist

• Constraints/indexes intentional
• Query count sane
• Views thin, services clear
• Migrations safe