モデルに対する初期データを投入する

It's sometimes useful to prepopulate your database with hard-coded data when you're first setting up an app. You can provide initial data with migrations or fixtures.

Provide initial data with migrations

To automatically load initial data for an app, create a data migration. Migrations are run when setting up the test database, so the data will be available there, subject to some limitations.

Provide data with fixtures

You can also provide data using fixtures, however, this data isn't loaded automatically, except if you use TransactionTestCase.fixtures.

フィクスチャは、Djangoがデータベースにインポートする方法を知っているデータのコレクションです。 すでにいくつかのデータがある場合、フィクスチャを作成する最も簡単な方法は manage.py dumpdata コマンドを使用することです。 もしくは、フィクスチャを手動で書くこともできます; フィクスチャは JSON、XML、または (PyYAMLをインストールして) YAML ドキュメントとして記述できます。 serialization documentation でサポートされている各 serialization formats の詳細を確認できます。

As an example, though, here's what a fixture for a Person model might look like in JSON:

[
  {
    "model": "myapp.person",
    "pk": 1,
    "fields": {
      "first_name": "John",
      "last_name": "Lennon"
    }
  },
  {
    "model": "myapp.person",
    "pk": 2,
    "fields": {
      "first_name": "Paul",
      "last_name": "McCartney"
    }
  }
]

YAML のフィクスチャだと以下のようになります:

- model: myapp.person
  pk: 1
  fields:
    first_name: John
    last_name: Lennon
- model: myapp.person
  pk: 2
  fields:
    first_name: Paul
    last_name: McCartney

このデータは、アプリケーション内の fixtures ディレクトリ内に保存しておくことができます。

You can load data by calling manage.py loaddata <fixturename>, where <fixturename> is the name of the fixture file you've created. Each time you run loaddata, the data will be read from the fixture and reloaded into the database. Note this means that if you change one of the rows created by a fixture and then run loaddata again, you'll wipe out any changes you've made.

Tell Django where to look for fixture files

By default, Django looks for fixtures in the fixtures directory inside each app for, so the command loaddata sample will find the file my_app/fixtures/sample.json. This works with relative paths as well, so loaddata my_app/sample will find the file my_app/fixtures/my_app/sample.json.

Django also looks for fixtures in the list of directories provided in the FIXTURE_DIRS setting.

To completely prevent default search form happening, use an absolute path to specify the location of your fixture file, e.g. loaddata /path/to/sample.

Namespace your fixture files

Django will use the first fixture file it finds whose name matches, so if you have fixture files with the same name in different applications, you will be unable to distinguish between them in your loaddata commands. The easiest way to avoid this problem is by namespacing your fixture files. That is, by putting them inside a directory named for their application, as in the relative path example above.

参考

フィクスチャは テストフレームワーク でも利用でき、テスト環境の一貫性を保つのに役立ちます。