Use a separate models for events' locations

gestion/migrations/0003_events.py

@@ -18,21 +18,42 @@ def import_events(apps, schema_editor):
         for name in model_names
     ]
 
-    # Moving the data into the new table
-    for OldModel, NewModel in models:
+    # The old Event.location field becomes a table: we need to create an entry
+    # in this table for each value of the old `location` field.
+    OldEvent, NewEvent = models[0]
+    Location = apps.get_model("gestion", "Location")
+    locations = []
+    events = []
+    for event in OldEvent.objects.values():
+        locations.append(Location(name=event["location"]))
+        events.append(event)
+    Location.objects.bulk_create(locations)
+    map_loc = {
+        loc.name: loc
+        for loc in Location.objects.all()
+    }
+    for event in events:
+        event["location"] = map_loc[event["location"]]
+    NewEvent.objects.bulk_create([
+        NewEvent(**event)
+        for event in events
+    ])
+
+    # Do not forget to link all the existing event to the COF group
+    cof = apps.get_model("auth", "Group").objects.get(name="cof_buro")
+    for event in NewEvent.objects.all():
+        event.associations.add(cof)
+
+    # Migrating the other models is straigtforward
+    for OldModel, NewModel in models[1:]:
         NewModel.objects.bulk_create([
             NewModel(**values)
             for values in OldModel.objects.values()
         ])
 
-    # Linking all the existing event to the COF group
-    cof = apps.get_model("auth", "Group").objects.get(name="cof_buro")
-    _, NewEvent = models[0]
-    for event in NewEvent.objects.all():
-        event.associations.add(cof)
-
 
 def restore_events(apps, schema_editor):
+    # TODO?
     raise NotImplementedError
 
 
@@ -45,12 +66,37 @@ class Migration(migrations.Migration):
     ]
 
     operations = [
+        migrations.CreateModel(
+            name='Location',
+            fields=[
+                (
+                    'id',
+                    models.AutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name='ID'
+                    )
+                ),
+                (
+                    'name',
+                    models.CharField(max_length=200, verbose_name='Lieu')
+                ),
+            ],
+            options={
+                'verbose_name': 'lieu',
+                'verbose_name_plural': 'lieux',
+            },
+        ),
         migrations.CreateModel(
             name='Event',
             fields=[
                 ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
                 ('title', models.CharField(max_length=200, verbose_name='Titre')),
-                ('location', models.CharField(max_length=200, verbose_name='Lieu')),
+                ('location', models.ForeignKey(
+                    on_delete=django.db.models.deletion.PROTECT,
+                    to='gestion.Location'
+                )),
                 ('start_date', models.DateTimeField(blank=True, null=True, verbose_name='Date de début')),
                 ('end_date', models.DateTimeField(blank=True, null=True, verbose_name='Date de fin')),
                 ('description', models.TextField(blank=True, verbose_name='Description')),

gestion/models.py

@@ -118,10 +118,18 @@ class ClubUser(models.Model):
 # Events
 # ---
 
+class Location(models.Model):
+    name = models.CharField("Lieu", max_length=200)
+
+    class Meta:
+        verbose_name = "lieu"
+        verbose_name_plural = "lieux"
+
+
 class Event(models.Model):
     associations = models.ManyToManyField(Group, related_name="events")
     title = models.CharField("Titre", max_length=200)
-    location = models.CharField("Lieu", max_length=200)
+    location = models.ForeignKey(Location, on_delete=models.PROTECT)
     start_date = models.DateTimeField("Date de début", blank=True, null=True)
     end_date = models.DateTimeField("Date de fin", blank=True, null=True)
     description = models.TextField("Description", blank=True)