我对我正在创建的一个简单的Django项目有一个问题.我这个项目的目标是使用Django Admin提供的工具来管理我已经拥有的数据库.

我继续解释我已经做了什么,但没有像预期的那样工作.

这是我的外部模型,使用inspectdb命令生成:

class Paises(models.Model):
    id_country = models.IntegerField(db_column='ID_COUNTRY', primary_key=True)
    country_name = models.TextField(db_column='COUNTRY_NAME', blank=True, null=True)
    country_phone_code = models.IntegerField(db_column='COUNTRY_PHONE_CODE', blank=True, null=True)

    class Meta:
        managed = False
        db_table = 'PAISES'
        verbose_name_plural = "Paises"

    def __str__(self):
        return self.country_name

然后,这是注册模型的管理类(如the documentation所示):

class PaisesAdminModel(admin.ModelAdmin):
    using = "external"
    list_display = ['id_country', 'country_name', 'country_phone_code']
    search_fields = ("country_name",)
    list_display_links = ('id_country', 'country_name')

    def save_model(self, request, obj, form, change):
        obj.save(using=self.using)

    def delete_model(self, request, obj):
        obj.delete(using=self.using)

    def get_queryset(self, request):
        return super().get_queryset(request).using(self.using)

    def formfield_for_foreignkey(self, db_field, request, **kwargs):
        return super().formfield_for_foreignkey(
            db_field, request, using=self.using, **kwargs
        )

    def formfield_for_manytomany(self, db_field, request, **kwargs):
        return super().formfield_for_manytomany(
            db_field, request, using=self.using, **kwargs
        )


admin.site.register(Paises, PaisesAdminModel)

然后我跑了python manage.py makemigrationspython manage.py migrate,看起来一切正常,但随后我发现了以下行为:

  • 模型正确列出,所有列和信息都正常,如果我使用ForeignKey,我甚至可以看到另一个模型的名称.
  • 我可以毫不费力地移除物体,这个功能似乎起作用了.(删除_模型)
  • 我可以编辑现有模型,甚至可以使用外键
  • I can't创造新模式
  • I can't从与外键相关的另一个模型中进行筛选

当我try 保存对象时,查看错误跟踪,可以看到错误:

Exception Value: relation "PAISES" does not exist LINE 1: SELECT 1 AS "a" FROM "PAISES" WHERE "PAISES"."ID_COUNTRY" = ...

它还试图使用默认数据库,尽管我指定使用外部数据库

enter image description here

这是完整的堆栈跟踪:

Environment:


Request Method: POST
Request URL: http://127.0.0.1:8000/admin/zonas_geograficas/paises/add/

Django Version: 4.1.7
Python Version: 3.10.6
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'usuarios',
 'zonas_geograficas']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']



Traceback (most recent call last):
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/db/backends/utils.py", line 89, in _execute
    return self.cursor.execute(sql, params)

The above exception (relation "PAISES" does not exist
LINE 1: SELECT 1 AS "a" FROM "PAISES" WHERE "PAISES"."ID_COUNTRY" = ...
                             ^
) was the direct cause of the following exception:
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/core/handlers/exception.py", line 56, in inner
    response = get_response(request)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/core/handlers/base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/contrib/admin/options.py", line 686, in wrapper
    return self.admin_site.admin_view(view)(*args, **kwargs)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/utils/decorators.py", line 134, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/views/decorators/cache.py", line 62, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/contrib/admin/sites.py", line 242, in inner
    return view(request, *args, **kwargs)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/contrib/admin/options.py", line 1891, in add_view
    return self.changeform_view(request, None, form_url, extra_context)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/utils/decorators.py", line 46, in _wrapper
    return bound_method(*args, **kwargs)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/utils/decorators.py", line 134, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/contrib/admin/options.py", line 1751, in changeform_view
    return self._changeform_view(request, object_id, form_url, extra_context)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/contrib/admin/options.py", line 1797, in _changeform_view
    form_validated = form.is_valid()
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/forms/forms.py", line 205, in is_valid
    return self.is_bound and not self.errors
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/forms/forms.py", line 200, in errors
    self.full_clean()
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/forms/forms.py", line 439, in full_clean
    self._post_clean()
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/forms/models.py", line 498, in _post_clean
    self.validate_unique()
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/forms/models.py", line 507, in validate_unique
    self.instance.validate_unique(exclude=exclude)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/db/models/base.py", line 1207, in validate_unique
    errors = self._perform_unique_checks(unique_checks)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/db/models/base.py", line 1317, in _perform_unique_checks
    if qs.exists():
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/db/models/query.py", line 1226, in exists
    return self.query.has_results(using=self.db)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/db/models/sql/query.py", line 592, in has_results
    return compiler.has_results()
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/db/models/sql/compiler.py", line 1366, in has_results
    return bool(self.execute_sql(SINGLE))
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/db/models/sql/compiler.py", line 1398, in execute_sql
    cursor.execute(sql, params)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/db/backends/utils.py", line 102, in execute
    return super().execute(sql, params)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/db/backends/utils.py", line 67, in execute
    return self._execute_with_wrappers(
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/db/backends/utils.py", line 80, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/db/backends/utils.py", line 84, in _execute
    with self.db.wrap_database_errors:
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/db/utils.py", line 91, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/db/backends/utils.py", line 89, in _execute
    return self.cursor.execute(sql, params)

Exception Type: ProgrammingError at /admin/zonas_geograficas/paises/add/
Exception Value: relation "PAISES" does not exist
LINE 1: SELECT 1 AS "a" FROM "PAISES" WHERE "PAISES"."ID_COUNTRY" = ...
                             ^

我希望你能看到一些我看不到的东西,提前谢谢.

Traceback of the first answer

Watching for file changes with StatReloader
Exception in thread django-main-thread:
Traceback (most recent call last):
  File "/usr/lib/python3.10/threading.py", line 1016, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.10/threading.py", line 953, in run
    self._target(*self._args, **self._kwargs)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/utils/autoreload.py", line 64, in wrapper
    fn(*args, **kwargs)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/core/management/commands/runserver.py", line 125, in inner_run
    autoreload.raise_last_exception()
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/utils/autoreload.py", line 87, in raise_last_exception
    raise _exception[1]
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/core/management/__init__.py", line 398, in execute
    autoreload.check_errors(django.setup)()
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/utils/autoreload.py", line 64, in wrapper
    fn(*args, **kwargs)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/apps/registry.py", line 116, in populate
    app_config.import_models()
  File "/home/javif/Documents/GitHub/AdminPanel/venv/lib/python3.10/site-packages/django/apps/config.py", line 269, in import_models
    self.models_module = import_module(models_module_name)
  File "/usr/lib/python3.10/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 883, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "/home/javif/Documents/GitHub/AdminPanel/zonas_geograficas/models.py", line 11, in <module>
    class Paises(models.Model):
  File "/home/javif/Documents/GitHub/AdminPanel/zonas_geograficas/models.py", line 27, in Paises
    objects = PaisesManager()
TypeError: Manager.__init__() missing 1 required positional argument: 'rootnode'

推荐答案

.using是不够的.Django执行unique次判断,省略了using次.但是,您可以通过覆盖_default_manager来修复此问题:

from django.db.models import Manager


class PaisesManager(Manager):
    def get_queryset(self, *args, **kwargs):
        return super().get_queryset(*args, **kwargs).using('external')


class Paises(models.Model):
    id_country = models.IntegerField(db_column='ID_COUNTRY', primary_key=True)
    country_name = models.TextField(
        db_column='COUNTRY_NAME', blank=True, null=True
    )
    country_phone_code = models.IntegerField(
        db_column='COUNTRY_PHONE_CODE', blank=True, null=True
    )

    class Meta:
        managed = False
        db_table = 'PAISES'
        verbose_name_plural = 'Paises'
        base_manager_name = 'objects'
        default_manager_name = 'objects'

    def __str__(self):
        return self.country_name

    objects = PraisesManager()

事实上,令人惊讶的是,Django的许多"机械师"都在不知不觉地在使用它.

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