When writing Django migrations, avoid importing and referencing external models directly. Django migrations use auto-generated model classes based on the migration state at that point, not the current model definitions. These migration-specific models ensure compatibility with the database schema as it existed at that migration's point in time. Instead of importing models directly, use the `apps.get_model()` method provided in migration functions to access the correct version of a model: ```python # Bad practice: from sentry.models.organization import Organization def migrate_data(apps, schema_editor): # Wrong: Organization here is the current model, not the migration state model orgs = Organization.objects.filter(active=True) # ... ``` ```python # Good practice: def migrate_data(apps, schema_editor): # Correct: Gets the Organization model as it exists at migration time Organization = apps.get_model("sentry", "Organization") orgs = Organization.objects.filter(active=True) # ... ``` This approach ensures migrations remain functional even as your models evolve over time, preventing subtle bugs that could corrupt data or break migration sequences.