from django.db import migrations def rebuild_mptt(apps, schema_editor): TenantGroup = apps.get_model('tenancy', 'TenantGroup') for i, tenantgroup in enumerate(TenantGroup.objects.all(), start=1): TenantGroup.objects.filter(pk=tenantgroup.pk).update(tree_id=i) class Migration(migrations.Migration): dependencies = [ ('tenancy', '0007_nested_tenantgroups'), ] operations = [ migrations.RunPython( code=rebuild_mptt, reverse_code=migrations.RunPython.noop ), ]