Djangoのモデル定義のUniqueConstraintsを使用するとFieldDoesNotExistが発生する

前提・実現したいこと

Djangoを勉強中の初心者です。
手習いに、通貨換算を行うアプリケーションを作成しようとしています。

そこで、通貨ペアを保持するモデルを定義したのですが、
どうもUniqueConstraintsを定義するとmigrateを叩いた時にエラーが発生するようです。

constraintsでは、同一の基軸通貨、決済通貨、レート種別に対しては1つのレートのみ登録できるようにしようとしています。

以下に実際のエラーメッセージとソースコードを記載いたしますので、
もし解決方法をご存知の方がいらっしゃれば、是非お知恵をお借りしたく。

発生している問題・エラーメッセージ

  Applying myApp.0001_initial...Traceback (most recent call last):
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\db\models\options.py", line 581, in get_field
    return self.fields_map[field_name]
KeyError: 'BASE_CURRENCY'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "manage.py", line 21, in <module>
    main()
  File "manage.py", line 17, in main
    execute_from_command_line(sys.argv)
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\core\management\__init__.py", line 401, in execute_from_command_line
    utility.execute()
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\core\management\__init__.py", line 395, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\core\management\base.py", line 328, in run_from_argv
    self.execute(*args, **cmd_options)
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\core\management\base.py", line 369, in execute
    output = self.handle(*args, **options)
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\core\management\base.py", line 83, in wrapped
    res = handle_func(*args, **kwargs)
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\core\management\commands\migrate.py", line 233, in handle
    fake_initial=fake_initial,
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\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 "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\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 "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\db\migrations\executor.py", line 245, in apply_migration
    state = migration.apply(state, schema_editor)
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\db\migrations\migration.py", line 124, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\db\migrations\operations\models.py", line 822, in database_forwards
    schema_editor.add_constraint(model, self.constraint)
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\db\backends\sqlite3\schema.py", line 406, in add_constraint
    self._remake_table(model)
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\db\backends\sqlite3\schema.py", line 280, in _remake_table
    self.create_model(new_model)
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\db\backends\base\schema.py", line 322, in create_model
    sql, params = self.table_sql(model)
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\db\backends\base\schema.py", line 193, in table_sql
    constraints = [constraint.constraint_sql(model, self) for constraint in model._meta.constraints]
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\db\backends\base\schema.py", line 193, in <listcomp>
    constraints = [constraint.constraint_sql(model, self) for constraint in model._meta.constraints]
  File "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\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 "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\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 "C:\Users\xxxxx\PycharmProjects\myProject\venv\lib\site-packages\django\db\models\options.py", line 583, in get_field
    raise FieldDoesNotExist("%s has no field named '%s'" % (self.object_name, field_name))
django.core.exceptions.FieldDoesNotExist: NewFxRate has no field named 'BASE_CURRENCY'

該当のソースコード

Python
1from django.db import models
2
3
4class FxRate(models.Model):
5    """
6    為替レート(基軸通貨/決済通貨)
7    """
8
9    objects = models.Manager()
10
11    # id = AutoField(primary_key=True)  # 自動的に追加されるため定義不要
12
13    base_currency = models.CharField(
14        verbose_name="基軸通貨", name="Base Currency",
15        blank=False, null=False, max_length=3,
16        db_column="BASE_CURRENCY"
17    )
18
19    quote_currency = models.CharField(
20        verbose_name="決済通貨", name="Quote Currency",
21        blank=False, null=False, max_length=3,
22        db_column="QUOTE_CURRENCY"
23    )
24
25    rate_type = models.CharField(
26        verbose_name="レート種別", name="Rate Type",
27        blank=False, null=False, max_length=3,
28        db_column="RATE_TYPE"
29    )
30
31    rate = models.DecimalField(
32        verbose_name="為替レート", name="FX Rate",
33        blank=False, null=False, decimal_places=2, max_digits=6,
34        db_column="FX_RATE"
35    )
36
37    class Meta:
38        db_table = "FX_RATE"
39        constraints = [
40            models.UniqueConstraint(
41                fields=['BASE_CURRENCY', 'QUOTE_CURRENCY', 'RATE_TYPE'],
42                name='FX_RATE_CURRENCIES_AND_RATE_TYPE_UNIQUE'
43            )
44        ]