Question

I got an error I don’t understand !

cannot import name Item

In my model, I have items. These items are required for actions. But some of these items have an effect on actions :

items

from django.db import models
from effects.models import Effect

class Type(models.Model):
    name = models.CharField(max_length=200)

    def __unicode__(self):
         return self.name

class Item(models.Model):
    name = models.CharField(max_length=200)
    description = models.CharField(max_length=200)
    type = models.ForeignKey(Type)
    quality = models.IntegerField()
    effects = models.ManyToManyField(Effect,through='ItemEffect',blank=True)
    item_requirement = models.ManyToManyField('self',through='ItemCraft',symmetrical=False,blank=True)
points = models.IntegerField()

    def __unicode__(self):
        return self.name

class Food(Item):
    ap = models.IntegerField()

class Tool(Item):
    durability = models.IntegerField()

[....]

class ItemEffect(models.Model):
    item = models.ForeignKey(Item)
    effect = models.ForeignKey(Effect)

def __unicode__(self):
    return self.item.name+':'+str.lower(self.effect.name)

class Meta:
    verbose_name_plural = 'items effects'

class ItemCraft(models.Model):
    item = models.ForeignKey(Item,related_name='%(class)s_item_crafted')
    item_requirement = models.ForeignKey(Item,related_name='%(class)s_item_required')
    number = models.IntegerField()

    def __unicode__(self):
        return self.item.name+' requires '+str.lower(self.item.name)+'('+self.number+')'

    class Meta:
        verbose_name_plural = 'items crafts'

actions

from django.db import models
from items.models import Item

class Action(models.Model):
    name = models.CharField(max_length=200)
    description = models.CharField(max_length=200)
    pa = models.IntegerField()

    def __unicode__(self):
        return self.name

class CraftAction(Action):
    item = models.ForeignKey(Item)

    def __unicode__(self):
        return self.item.name+'\'s craft'

    class Meta:
        verbose_name_plural = 'crafts actions'

effects

from django.db import models
from actions.models import Action

class Effect(models.Model):
    action = models.ForeignKey

class ApEffect(Effect):
    ap = models.IntegerField()

Answer 1

There is a circular import in your code, that’s why the Item can’t be imported in action.

You can solve the problem by removing the import of a class in one of your files, and replacing it with a string containing the name of the class, as explained in the documentation. For example :

effects = models.ManyToManyField('effects.Effect',through='ItemEffect',blank=True)