Django-parler unique_together constraint between translated and normal field - python-3.x

Question

I want to make unique_together constraint with django-parler between translated field and normal field.
I'd like to do this:
class Part(TranslatableModel):
code = CharField('code')
translations = TranslatedFields(
name = CharField('name')
)
class Meta:
constraints = [
UniqueConstraint(
fields=['code', 'name'],
name='constraint_name',
)
]
but then I get error:
Traceback (most recent call last):
File "manage.py", line 14, in <module>
execute_from_command_line(sys.argv)
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
utility.execute()
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/core/management/__init__.py", line 375, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/core/management/base.py", line 323, in run_from_argv
self.execute(*args, **cmd_options)
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/core/management/base.py", line 364, in execute
output = self.handle(*args, **options)
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/core/management/base.py", line 83, in wrapped
res = handle_func(*args, **kwargs)
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/core/management/commands/migrate.py", line 234, in handle
fake_initial=fake_initial,
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/db/migrations/executor.py", line 117, in migrate
state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/db/migrations/executor.py", line 147, in _migrate_all_forwards
state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/db/migrations/executor.py", line 245, in apply_migration
state = migration.apply(state, schema_editor)
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/db/migrations/migration.py", line 124, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/db/migrations/operations/models.py", line 827, in database_forwards
schema_editor.add_constraint(model, self.constraint)
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/db/backends/sqlite3/schema.py", line 405, in add_constraint
self._remake_table(model)
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/db/backends/sqlite3/schema.py", line 279, in _remake_table
self.create_model(new_model)
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 296, in create_model
constraints = [constraint.constraint_sql(model, self) for constraint in model._meta.constraints]
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 296, in <listcomp>
constraints = [constraint.constraint_sql(model, self) for constraint in model._meta.constraints]
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/db/models/constraints.py", line 89, in constraint_sql
fields = [model._meta.get_field(field_name).column for field_name in self.fields]
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/db/models/constraints.py", line 89, in <listcomp>
fields = [model._meta.get_field(field_name).column for field_name in self.fields]
File "/home/lauri/työt/p/venv/lib/python3.6/site-packages/django/db/models/options.py", line 567, in get_field
raise FieldDoesNotExist("%s has no field named '%s'" % (self.object_name, field_name))
django.core.exceptions.FieldDoesNotExist: NewPart has no field named 'name'
I'm not very aware of insides of django-parler so I'm not able to move forward with this.

Answer 1

When you make migrations there will be two tables Part and PartTranslation. What you want is single translation for single post. So the following lines solves your problem
translations = TranslatedFields(
name = CharField('name'),
meta={'unique_together': [('name', 'language_code')]}
)
For uniqueness of Parts just make the code field unique.
code = CharField('code', unique=True)