python - 某些模型无法加载 Django 自然键

Question

我有一个包含多个模型的项目，所有这些模型都在实现自然键。其中大多数都在工作，但是当我使用自然键导出时，有一个模型（到目前为止）拒绝加载。

注意：如果我在导出时不使用自然键，它可以工作。

不会加载的模型是CampaignTransaction， Campaign 有效。

这是我的模型和经理：

class CampainManager(models.Manager):
    def get_by_natural_key(self, title, org):
        return self.get(title=title, org__name=org)

class Campaign(models.Model):
    """Donation Campaign information
    **Referenced By:** :class:`CampaignTransaction`"""
    title = models.CharField(max_length=100)
    """Campaign Title"""
    org = models.ForeignKey(Organization, on_delete=models.PROTECT)
    """:class:`~FundingHub.common.models.Organization` conducting campaign"""
    description = models.TextField()
    """Description of campaign"""
    start_date = models.DateTimeField()
    """Start date of campaign"""
    end_date = models.DateTimeField()
    """End date of campaign"""

    objects = CampainManager()

    def __str__(self):
        return self.title

    def natural_key(self):
        return (self.title, self.org.natural_key())
    natural_key.dependencies = ['common.Organization']

    class Meta:
        unique_together = ('org', 'title')

class CampaignTransactionManager(models.Manager):
    def get_by_natural_key(self, cc_type, trans_id, campaign):
        return self.get(cc_type=cc_type, cc_transaction_id=trans_id, campaign__name=campaign)

class CampaignTransaction(models.Model):
    """A single donation"""

    campaign = models.ForeignKey(Campaign, on_delete=models.PROTECT)
    """The :class:`Campaign` that is being donated to"""
    user = models.ForeignKey(get_user_model(), on_delete=models.PROTECT)
    """The :class:`~FundingHub.common.models.User` that is making the donation"""
    amount = models.DecimalField(max_digits=9, decimal_places=2)
    """Amount of donation"""
    cc_type = models.CharField(max_length=3, choices=CC_TYPES)
    """Type of credi card used to make the donation :data:`~FundingHub.common.models.CC_TYPES` contains the valid options"""
    cc_transaction_id = models.CharField(max_length=200)
    """Credit card transaction ID"""
    trans_date = models.DateTimeField()
    """Date and time of transaction"""

    objects = CampaignTransactionManager()

    def __str__(self):
        return F'{self.campaign.title} - {self.cc_transaction_id} - {self.amount}'

    def natural_key(self):
        return  (self.cc_type, self.cc_transaction_id, self.campaign.natural_key())
    natural_key.dependencies = ['donations.Campaign']

    class Meta:
        unique_together = ('cc_type', 'cc_transaction_id')

这是输出python manage.py dumpdata donations --database test --indent=4 --natural-foreign > xx.json：

[
{
    "model": "donations.campaign",
    "pk": 1,
    "fields": {
        "title": "Taco Tuesday",
        "org": [
            "Tacos For Freedom"
        ],
        "description": "Tacos on Tuesday",
        "start_date": "2020-05-28T18:08:13Z",
        "end_date": "2020-05-28T22:00:00Z"
    }
},
{
    "model": "donations.campaigntransaction",
    "pk": 1,
    "fields": {
        "campaign": [
            "Taco Tuesday",
            [
                "Tacos For Freedom"
            ]
        ],
        "user": [
            "[e-mail]"
        ],
        "amount": "1000.00",
        "cc_type": "VIS",
        "cc_transaction_id": "VIS-1234567890",
        "trans_date": "2020-05-28T19:33:48Z"
    }
}
]

然后我尝试使用python manage.py loaddata --database test xx.json我收到错误重新加载它：

Traceback (most recent call last):
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/backends/utils.py", line 86, in _execute
    return self.cursor.execute(sql, params)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/backends/sqlite3/base.py", line 396, in execute
    return Database.Cursor.execute(self, query, params)
sqlite3.IntegrityError: NOT NULL constraint failed: donations_campaigntransaction.campaign_id

The above exception was the direct cause of the following exception:

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 "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line
    utility.execute()
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/core/management/__init__.py", line 395, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/core/management/base.py", line 328, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/core/management/base.py", line 369, in execute
    output = self.handle(*args, **options)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/core/management/commands/loaddata.py", line 72, in handle
    self.loaddata(fixture_labels)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/core/management/commands/loaddata.py", line 114, in loaddata
    self.load_label(fixture_label)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/core/management/commands/loaddata.py", line 181, in load_label
    obj.save(using=self.using)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/core/serializers/base.py", line 223, in save
    models.Model.save_base(self.object, using=using, raw=True, **kwargs)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/models/base.py", line 784, in save_base
    force_update, using, update_fields,
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/models/base.py", line 865, in _save_table
    forced_update)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/models/base.py", line 917, in _do_update
    return filtered._update(values) > 0
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/models/query.py", line 771, in _update
    return query.get_compiler(self.db).execute_sql(CURSOR)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1499, in execute_sql
    cursor = super().execute_sql(result_type)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1151, in execute_sql
    cursor.execute(sql, params)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/backends/utils.py", line 100, in execute
    return super().execute(sql, params)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/backends/utils.py", line 68, in execute
    return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/backends/utils.py", line 77, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/backends/utils.py", line 86, in _execute
    return self.cursor.execute(sql, params)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/utils.py", line 90, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/backends/utils.py", line 86, in _execute
    return self.cursor.execute(sql, params)
  File "/Users/alexthomas/.venvs/FHEnv/lib/python3.7/site-packages/django/db/backends/sqlite3/base.py", line 396, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.IntegrityError: Problem installing fixture '/Users/alexthomas/Projects/FundingHub/xx.json': Could not load donations.CampaignTransaction(pk=1): NOT NULL constraint failed: donations_campaigntransaction.campaign_id

它似乎在抱怨空值，但我看不到缺少什么。从夹具。

标签： pythondjangodjango-modelsdjango-fixturesnatural-key