【发布时间】：2020-05-24 20:03:23
【问题描述】：
我正在尝试在我的项目中运行 Django 迁移，但有些东西无法正常工作，我无法弄清楚会发生什么。
AuditableModelMixin 实体由我项目中的几乎所有实体扩展，并提供了几个用于审计目的的字段。尽管如此，迁移运行良好。虽然，对于Contract 模型，迁移正在创建以下两个单独的文件：
0001_initial.py
class Migration(migrations.Migration):
initial = True
dependencies = [
migrations.swappable_dependency(settings.AUTH_USER_MODEL),
]
operations = [
migrations.CreateModel(
name='Contract',
fields=[
('id', models.UUIDField(default=uuid.uuid4, editable=False, primary_key=True, serialize=False, verbose_name='identifier')),
('created_at', models.DateTimeField(auto_now_add=True, verbose_name='created at')),
('updated_at', models.DateTimeField(auto_now=True, verbose_name='updated at')),
('name', models.CharField(max_length=100, unique=True, verbose_name='name')),
('description', models.CharField(blank=True, max_length=1024, null=True, verbose_name='description')),
('created_by', models.ForeignKey(blank=True, db_column='created_by', null=True, on_delete=django.db.models.deletion.PROTECT, related_name='contract_created_by', to=settings.AUTH_USER_MODEL, verbose_name='created by')),
],
options={
'verbose_name': 'contract',
'verbose_name_plural': 'contracts',
'db_table': 'sacv"."contract',
},
),
]
0002_auto_20200524_1912.py（顺序会变，没关系）
class Migration(migrations.Migration):
initial = True
dependencies = [
migrations.swappable_dependency(settings.AUTH_USER_MODEL),
('contract', '0001_initial'),
('jurisdiction', '0001_initial'),
('state', '0001_initial'),
]
operations = [
migrations.AddField(
model_name='contract',
name='jurisdictions',
field=models.ManyToManyField(related_name='contracts', through='jurisdiction.Jurisdiction', to='state.State'),
),
migrations.AddField(
model_name='contract',
name='updated_by',
field=models.ForeignKey(blank=True, db_column='updated_by', null=True, on_delete=django.db.models.deletion.PROTECT, related_name='contract_updated_by', to=settings.AUTH_USER_MODEL, verbose_name='updated by'),
),
]
我不知道为什么，它将updated_by 放入一个单独的文件中。在我将ManyToMany 关系添加到Contract 模型中后，它开始发生。使用这种新方法，当我运行 python manage.py migrate 时，我收到以下错误：
Traceback (most recent call last):
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/sacv/manage.py", line 21, in <module>
main()
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/sacv/manage.py", line 17, in main
execute_from_command_line(sys.argv)
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line
utility.execute()
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/core/management/__init__.py", line 395, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/core/management/base.py", line 328, in run_from_argv
self.execute(*args, **cmd_options)
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/core/management/base.py", line 369, in execute
output = self.handle(*args, **options)
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/core/management/base.py", line 83, in wrapped
res = handle_func(*args, **kwargs)
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/core/management/commands/migrate.py", line 231, in handle
post_migrate_state = executor.migrate(
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/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/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/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/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/db/migrations/executor.py", line 245, in apply_migration
state = migration.apply(state, schema_editor)
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/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/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/db/migrations/operations/fields.py", line 110, in database_forwards
schema_editor.add_field(
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/db/backends/base/schema.py", line 480, in add_field
self.execute(sql, params)
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/db/backends/base/schema.py", line 142, in execute
cursor.execute(sql, params)
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 100, in execute
return super().execute(sql, params)
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 68, in execute
return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 77, in _execute_with_wrappers
return executor(sql, params, many, context)
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 86, in _execute
return self.cursor.execute(sql, params)
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/db/utils.py", line 90, in __exit__
raise dj_exc_value.with_traceback(traceback) from exc_value
File "/home/rodrigo/Workspace/fgv/sacv-p/src/backend/venv/lib/python3.8/site-packages/django/db/backends/utils.py", line 86, in _execute
return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: constraint "contract_updated_by_4a62e48c_fk_account_id" does not exist
Error when trying create and run Django migrations!
Failed! The script execution has finished with errors!
如果我更改迁移文件并将updated_by 放入第一个文件中，一切正常，但我不认为这是正确的方法。有人对这个问题有任何线索吗？
以下代码是与问题相关的类：
审计类
class AuditableModelMixin(models.Model):
created_at = models.DateTimeField(
_('created at'),
auto_now_add=True,
editable=False
)
created_by = models.ForeignKey(
'account.Account',
verbose_name=_('created by'),
db_column='created_by',
related_name='%(class)s_created_by',
null=True,
blank=True,
on_delete=models.PROTECT,
)
updated_at = models.DateTimeField(
_('updated at'),
auto_now=True,
)
updated_by = models.ForeignKey(
'account.Account',
verbose_name=_('updated by'),
db_column='updated_by',
related_name='%(class)s_updated_by',
null=True,
blank=True,
on_delete=models.PROTECT,
)
class Meta:
abstract = True
ordering = ['-created_at']
合同类
class Contract(
UUIDModelMixin,
AuditableModelMixin
):
jurisdictions = models.ManyToManyField(
State,
related_name='contracts',
through='jurisdiction.Jurisdiction',
through_fields=('contract', 'state')
)
name = models.CharField(_('name'), max_length=100, unique=True)
description = models.CharField(
_('description'),
max_length=1024,
blank=True,
null=True
)
class Meta:
db_table = 'sacv\".\"contract'
verbose_name = _('contract')
verbose_name_plural = _('contracts')
def __str__(self):
return self.description
管辖类别
class JurisdictionManager(models.Manager):
def get_queryset(self):
return super().get_queryset().filter(
active=True, ended_at__isnull=True
)
class Jurisdiction(
UUIDModelMixin,
EligibilityModelMixin,
AuditableModelMixin
):
contract = models.ForeignKey(
Contract,
verbose_name=_('contract'),
on_delete=models.PROTECT
)
state = models.ForeignKey(
State,
verbose_name=_('state'),
related_name="+", # Disable the reverse relation for State
on_delete=models.PROTECT
)
objects = JurisdictionManager()
class Meta:
db_table = 'sacv\".\"jurisdiction'
verbose_name = 'jurisdiction'
verbose_name_plural = 'jurisdictions'
def __str__(self):
return f"{self.contract.name}: {self.state}"
【问题讨论】：
标签： python django foreign-keys migration