thrillwiki_django_no_react/memory-bank/decisions/migration-progress.md

PGHistory Migration Progress

All Migrations Complete! 🎉

Latest Migration

• location/migrations/0002_locationevent_remove_historicallocation_content_type_and_more.py
  • Created LocationEvent model
  • Removed simple-history fields
  • Set up pghistory triggers
  • Cleaned up historical models

Previously Completed Migrations

1. Companies App

   • Created CompanyEvent and ManufacturerEvent
   • Removed Designer model
   • Set up pghistory triggers

2. Rides App

   • Created RideEvent and RideModelEvent
   • Removed simple-history fields
   • Updated Designer foreign key
   • Set up pghistory triggers

3. Parks App

   • Created ParkEvent and ParkAreaEvent models
   • Set up pghistory tracking triggers
   • Removed simple-history fields and models

4. Designers App

   • Created DesignerEvent model
   • Set up insert/update triggers
   • Full pghistory implementation

5. Moderation Models

   • Created EditSubmissionEvent model
   • Created PhotoSubmissionEvent model
   • Set up triggers for both models

Infrastructure Updates

1. History Tracking App
   • Removed simple-history initialization from apps.py
   • Updated base models to use pghistory
   • Added DiffMixin for tracking changes

Final Steps

1. Remove django-simple-history

# Update requirements.txt
- Remove django-simple-history==3.8.0

2. Clean Up Configuration

• Remove any remaining simple-history settings
• Update documentation for new history tracking
• Add migration guide for future models

3. Testing

1. Test all models:

   • Create/Update/Delete operations
   • Historical queries
   • Change tracking
   • Event context

2. Verify functionality:

   • Slug history lookups
   • Model relationships
   • Admin interfaces

4. Documentation Updates

1. Update model documentation
2. Add pghistory usage examples
3. Document migration patterns
4. Update contributor guide

Technical Notes

• PGHistory tracking implemented via triggers
• Event models store complete history
• Foreign key relationships preserved
• Context tracking available
• GeoDjango fields supported
• Improved query performance expected

Migration Statistics

✅ Designer Model ✅ Moderation Models ✅ Companies Models ✅ Rides Models ✅ Parks Models ✅ Location Models

Lessons Learned

1. Keep backward compatibility during transition
2. Migrate models in dependency order
3. Test thoroughly after each migration
4. Update related code incrementally
5. Maintain documentation throughout