[英]Django import error when trying to import a model from a different app
[英]Django import error when trying to migrate models from app to app
我在导入时遇到了奇怪的问题
自从我的一些应用变得非常庞大以来,我已经创建了新的应用并尝试将一些模块移到那里。
我创建了新的应用程序产品,并将其添加到我的设置文件中,并写在product / model.py中
from django.db import models
from author.decorators import with_author
from item.models import ItemGroup
from item.models import Material
# Create your models here.
@with_author
class Product(models.Model):
code = models.CharField(max_length=30, unique=True)
name = models.CharField(max_length=30)
description = models.TextField(null=True, blank=True)
creation_time = models.DateTimeField(auto_now_add=True, blank=True)
itemgroup = models.ForeignKey(ItemGroup, on_delete=models.PROTECT)
material = models.ForeignKey(Material, on_delete=models.PROTECT)
keywords = models.CharField(max_length=50,null=True, blank=True)
valid_from = models.DateTimeField(null=True, blank=True)
valid_to = models.DateTimeField(null=True, blank=True)
style1 = models.CharField(max_length=30,null=True, blank=True)
style2 = models.CharField(max_length=30,null=True, blank=True)
style3 = models.CharField(max_length=30,null=True, blank=True)
size = models.CharField(max_length=30,null=True, blank=True)
dimension = models.CharField(max_length=30,null=True, blank=True)
color = models.CharField(max_length=30,null=True, blank=True)
def __unicode__(self):
return u'%s %s %s' % ( self.id, self.code, self.name)
当我执行
>python manage.py makemigrations item
>python manage.py makemigrations product
我收到一个错误
Traceback (most recent call last):
File "manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "C:\Users\I812624\dev\mrp\lib\site-packages\django\core\management\__ini
__.py", line 338, in execute_from_command_line
utility.execute()
File "C:\Users\I812624\dev\mrp\lib\site-packages\django\core\management\__ini
__.py", line 312, in execute
django.setup()
File "C:\Users\I812624\dev\mrp\lib\site-packages\django\__init__.py", line 18
in setup
apps.populate(settings.INSTALLED_APPS)
File "C:\Users\I812624\dev\mrp\lib\site-packages\django\apps\registry.py", li
e 108, in populate
app_config.import_models(all_models)
File "C:\Users\I812624\dev\mrp\lib\site-packages\django\apps\config.py", line
198, in import_models
self.models_module = import_module(models_module_name)
File "c:\python27\Lib\importlib\__init__.py", line 37, in import_module
__import__(name)
File "C:\Users\I812624\dev\mrp\src\item\models.py", line 13, in <module>
from product.models import Product
File "C:\Users\I812624\dev\mrp\src\product\models.py", line 3, in <module>
from item.models import ItemGroup
ImportError: cannot import name ItemGroup
可能是什么问题呢 ?
这是我在item中的ItemGroup模型
@with_author
class ItemGroup(models.Model):
name = models.CharField(max_length=30)
description = models.TextField(null=True, blank=True)
creation_time = models.DateTimeField(auto_now_add=True)
subcategory = models.ForeignKey(SubCategory, on_delete=models.PROTECT)
keywords = models.CharField(max_length=50,null=True, blank=True)
#hierarchy = TreeForeignKey(Hierarchy, blank=True, null=True, related_name='cat')
def __unicode__(self):
return u'%s %s' % ( self.id, self.name)
您尝试进行交叉导入。 那是不允许的。 如果不需要,请"C:\\Users\\I812624\\dev\\mrp\\src\\item\\models.py"
的第13行。
或在第3行和第4行注释掉:
"C:\Users\I812624\dev\mrp\src\product\models.py"
并做:
itemgroup = models.ForeignKey("item.ItemGroup", on_delete=models.PROTECT)
material = models.ForeignKey("item.Material", on_delete=models.PROTECT)
我在这里猜测您正在进行循环导入。 item.models
某些item.models
正在尝试从product.models
导入某些内容,而product.models
某些内容正在尝试导入item.models
某些item.models
...
解决方案是完全避免它,方法是允许Django处理循环关系而不是Python, 就像在此问题的答案中一样 。
因此,在您的情况下,请在此处删除导入,而应像字符串一样引用它:
@with_author
class ItemGroup(models.Model):
# ...
subcategory = models.ForeignKey('product.SubCategory', on_delete=models.PROTECT)
# ...
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