Question

我有一个Django模型，我正在导入一些项目：

from django.db import models
from mcif.models.import_profile import ImportProfile
from mcif.models.import_file import ImportFile
from mcif.models.import_bundle import ImportBundle
from mcif.models.customer import Customer
#from mcif.models.account_import import AccountImport
from mcif.models.csv_row import CSVRow
import csv, cStringIO

它工作正常，但是当我取消评论该评论的那一行时，我得到了这个：

Traceback (most recent call last):
  File "./manage.py", line 11, in <module>
    execute_manager(settings)
  File "/usr/lib/pymodules/python2.6/django/core/management/__init__.py", line 438, in execute_manager
    utility.execute()
  File "/usr/lib/pymodules/python2.6/django/core/management/__init__.py", line 379, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/lib/pymodules/python2.6/django/core/management/base.py", line 191, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/usr/lib/pymodules/python2.6/django/core/management/base.py", line 220, in execute
    output = self.handle(*args, **options)
  File "/usr/lib/pymodules/python2.6/django/core/management/base.py", line 351, in handle
    return self.handle_noargs(**options)
  File "/usr/lib/pymodules/python2.6/django/core/management/commands/shell.py", line 18, in handle_noargs
    loaded_models = get_models()
  File "/usr/lib/pymodules/python2.6/django/db/models/loading.py", line 167, in get_models
    self._populate()
  File "/usr/lib/pymodules/python2.6/django/db/models/loading.py", line 64, in _populate
    self.load_app(app_name)
  File "/usr/lib/pymodules/python2.6/django/db/models/loading.py", line 78, in load_app
    models = import_module('.models', app_name)
  File "/usr/lib/pymodules/python2.6/django/utils/importlib.py", line 35, in import_module
    __import__(name)
  File "/home/jason/projects/mcifdjango/mcif/models/__init__.py", line 5, in <module>
    from mcif.models.account_import import AccountImport
  File "/home/jason/projects/mcifdjango/mcif/models/account_import.py", line 2, in <module>
    from mcif.models.generic_import import GenericImport
  File "/home/jason/projects/mcifdjango/mcif/models/generic_import.py", line 6, in <module>
    from mcif.models.account_import import AccountImport
ImportError: cannot import name AccountImport

为什么Django不喜欢这个特定的文件？

（我可以在控制台上自己加载AccountImport就好了。）

此外，如果看到它有AccountImport：

from django.db import models
from mcif.models.generic_import import GenericImport

class AccountImport(models.Model):

    id = models.BigIntegerField(primary_key=True)
    generic_import = models.ForeignKey(GenericImport)
    is_entirely_international = models.IntegerField()
    is_queued = models.IntegerField()
    created_at = models.DateTimeField()
    updated_at = models.DateTimeField()

    class Meta:
        db_table = u'account_import'
        app_name = 'mcif'

GenericImport：

from django.db import models
from mcif.models.import_profile import ImportProfile
from mcif.models.import_file import ImportFile
from mcif.models.import_bundle import ImportBundle
from mcif.models.customer import Customer
from mcif.models.csv_row import CSVRow
import csv, cStringIO

class GenericImport(models.Model):

    class Meta:
        db_table = u'generic_import'
        app_name = 'mcif'

    id = models.BigIntegerField(primary_key=True)
    import_profile = models.ForeignKey(ImportProfile)
    import_file = models.ForeignKey(ImportFile)
    notes = models.TextField()
    start_time = models.DateTimeField()
    end_time = models.DateTimeField()
    active = models.IntegerField()
    created_at = models.DateTimeField()
    updated_at = models.DateTimeField()
    unsavable_rows = models.TextField()
    import_bundle = models.ForeignKey(ImportBundle)
    is_queued = models.IntegerField()

    @classmethod
    def last(cls):
        all = GenericImport.objects.all()
        return all[len(all) - 1]

    def process(self):
        for line in self.import_file.file.split("\n")[:30]:
            f = cStringIO.StringIO(line)
            row = CSVRow()
            row.array = next(csv.reader(f))
            row.generic_import = self
            row.process()
            f.close()

    def specific_import(self):
        for model_name in ['TransactionImport', 'AccountImport']:
            specific_imports = eval(model_name + '.objects.filter(generic_import__pk=5)')
            if len(specific_imports) > 0:
                return specific_imports[0]
        return False

Answer 1

您有循环导入 - mcif.models.generic_import和mcif.models.account_import正试图互相导入。

请记住，Python不是Java，并且非常乐意在一个文件中包含多个类，特别是如果它们像这两个类似的密切相关。将它们放在一个mcif.models文件中。

Answer 2

这是循环模型依赖。

File "/home/jason/projects/mcifdjango/mcif/models/__init__.py", line 5, in <module>
    from mcif.models.account_import import AccountImport
File "/home/jason/projects/mcifdjango/mcif/models/account_import.py", line 2, in <module>
    from mcif.models.generic_import import GenericImport
File "/home/jason/projects/mcifdjango/mcif/models/generic_import.py", line 6, in <module>
    from mcif.models.account_import import AccountImport
ImportError: cannot import name AccountImport

如果您确实需要将这些模型分开，请查看http://docs.djangoproject.com/en/1.2/ref/models/fields/#django.db.models.ForeignKey以获得解决方案。您可以使用字符串来引用模型，而不是导入模型。

class Car(models.Model):
    manufacturer = models.ForeignKey('production.Manufacturer')

将使用Manufacturer模块中的production模型作为外键的目标。

Answer 3

看起来你在那里有一个循环导入。

  File "/home/jason/projects/mcifdjango/mcif/models/__init__.py", line 5, in <module>
    from mcif.models.account_import import AccountImport
  File "/home/jason/projects/mcifdjango/mcif/models/account_import.py", line 2, in <module>
    from mcif.models.generic_import import GenericImport
  File "/home/jason/projects/mcifdjango/mcif/models/generic_import.py", line 6, in <module>
    from mcif.models.account_import import AccountImport

导入__init__.py的{{1}}导入AccountImport然后再次导入GenericImport，但我不确定如何导入它根本就可以正常工作。

您的AccountImport确实需要导入GenericImport吗？看起来像破碎的等级。

修改 :(用于更新）

AccountImport

def specific_import(self): for model_name in ['TransactionImport', 'AccountImport']: specific_imports = eval(model_name + '.objects.filter(generic_import__pk=5)') if len(specific_imports) > 0: return specific_imports[0] return False行不良行为。这里肯定有比这更好的模式。您的通用类不应该对您的具体实现有任何了解或依赖，更不用说eval在实际代码中几乎没有任何地方。

由于某种原因，Django不想导入一个特定的模型

3 个答案: