django抽象模型继承导入

Question

I wonder how i can import an abstract model into another app

world_elements holds:

class Location(models.Model):
    """
    Holds x,y coordinates of a virtual 2d map. 
    """

    x = models.IntegerField()
    y = models.IntegerField()

    class Meta:
        abstract = True

    def __unicode__(self):
        return "%s, %s" % (self.x, self.y)

now in another app i try:

from world_elements.models import Location

class NpcTown(Location):
    """
    A town with their coordinates trianinggrounds quest office and all other relevant attributes
    """

    # general town information
    name = models.CharField(max_length = 63)
    flavor = models.TextField(max_length = 511)
    guild = models.ForeignKey(NpcGuild)

    # locations
    trainingground = models.ForeignKey(TrainingGround, null=True)

    def __unicode__(self):
        return self.name

but now i get ImportError: cannot import name Location

How do i import an abstract model?

Answer 1

Simplifying the names of the classes a bit, the following works for me in Django 1.7, which is the latest stable release at the time of this writing.

Directory layout

    project
          \_ apps
              \_ __init__.py
              \_ A
              \_ B
          \_ config
              \_ __init__.py
              \_ settings.py
              \_ urls.py
              \_ wsgi.py
          \_ data
          \_ makefile
          \_ manage.py
          \_ README.md

In the above, app A contains the abstract model. B uses it, as follows:

Abstract Class(es)

class AModel(Model):
    ...
    class Meta:
        abstract = True

Then

Concrete Class(es)

from apps.A.models import AModel

class BModel(AModel):
    ...
    blah = "ayyo"

Note that apps, A, and B all must contain an __init__.py file.

Don't be afraid to break free of the Django directory layout conventions imposed by manage.py start{app,project} . Doing so will free your mind and you will love having things neatly organized.

Another thing that helps debugging module imports is simply print ing the module imported. Then you can tell what is actually being resolved. For example:

from apps.A.models import AModel
print AModel # <class 'apps.A.models.AModel'>

And:

import apps
print apps # <module 'apps' from '/home/g33k/gits/checkouts/my/project/apps/__init__.pyc'>

Answer 2

In a normal structure like this:

my_project
  - /my_project
    - /settings.py
  - /app1
    - /models.py
      * class Model1...
  - /app2
    - /models.py
      * class Model2...

From app1/models.py this worked for me:

from django.db import models
from my_project.app1.models import Model1

class Model2(Model1):
    ...

Using Django 11.1

Answer 3

尝试

from world_elements import Location