breccia-mapper/people/migrations/0021_refactor_person_disciplines.py

# Generated by Django 2.2.10 on 2020-06-24 14:19

from django.db import migrations, models


def migrate_forward(apps, schema_editor):
    Person = apps.get_model('people', 'Person')

    for person in Person.objects.all():
        try:
            person.disciplines = person.discipline.name
            person.save()

        except AttributeError:
            pass


def migrate_backward(apps, schema_editor):
    Person = apps.get_model('people', 'Person')
    Discipline = apps.get_model('people', 'Discipline')

    for person in Person.objects.all():
        try:
            discipline_str = person.disciplines.split(',')[0]

        except AttributeError:
            pass

        else:
            # Returns None if not found - doesn't raise exception
            discipline = Discipline.objects.filter(name=discipline_str).first()

            if not discipline:
                discipline = Discipline.objects.create(
                    name=discipline_str,
                    code=discipline_str
                    if len(discipline_str) < 15 else discipline_str[:15])

            person.discipline = discipline
            person.save()


class Migration(migrations.Migration):

    dependencies = [
        ('people', '0020_person_organisation_started_date'),
    ]

    operations = [
        migrations.AddField(
            model_name='person',
            name='disciplines',
            field=models.CharField(blank=True, max_length=255, null=True),
        ),
        migrations.RunPython(migrate_forward, migrate_backward),
        migrations.RemoveField(
            model_name='person',
            name='discipline',
        ),
        migrations.DeleteModel(name='Discipline', ),
    ]