python – django：使用自然外键加载fixture失败,出现’ValueErr

class StateManager(models.Manager):
    def get_by_natural_key(self,name):
        return self.get(name=name)


class DistrictManager(models.Manager):
    def get_by_natural_key(self,name,state):
        return self.get(name=name,state=state)

class State(models.Model):

    class Meta:
        verbose_name = "State"
        verbose_name_plural = "States"
        permissions = (
            ('access_state','Can access States'),)

    COUNTRIES = (
        ('India','India'),('USA','USA'),('Thailand','Thailand'),)

    # Managers
    objects = StateManager()

    # Database fields
    name = models.CharField(
        'Name',max_length=100,unique=True,help_text='''
        100 chars max
        '''
    )
    code = models.CharField(
        'Code',max_length=10,help_text='''
        10 chars max
        ''',null=True,blank=True
    )
    country = models.CharField(
        max_length=50,default="India",choices=COUNTRIES,blank=False,null=False
    )

    def __str__(self):
        return self.name

    def natural_key(self):
        return (self.name,)


class District(models.Model):

    class Meta:
        verbose_name = "District"
        verbose_name_plural = "Districts"
        unique_together = (
            (
                "state","name"
            ),)

    # Managers
    objects = DistrictManager()

    # Database fields
    name = models.CharField(
        'Name',blank=True
    )
    state = models.ForeignKey(State)

    def __str__(self):
        return self.name

    def natural_key(self):
        return (self.name,) + self.state.natural_key()
    natural_key.dependencies = ['parties.state']

我对区模型的夹具是……

[
{
    "model": "parties.district","fields": {
        "name": "North Andaman","state": [
            "Andaman and Nicobar"
        ],"code": "NA"
    }
},{
    "model": "parties.district","fields": {
        "name": "South Andaman","code": "SA"
    }
}
]

实际上,夹具是由django的’dumpdata’本身生成的.

但是,在尝试加载夹具时,我收到以下错误…

ValueError: invalid literal for int() with base 10: 'Andaman and Nicobar'

The full trace is given below ...

Traceback (most recent call last):
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/core/serializers/json.py",line 79,in Deserializer
    for obj in PythonDeserializer(objects,**options):
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/core/serializers/python.py",line 157,in Deserializer
    obj = base.build_instance(Model,data,db)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/core/serializers/base.py",line 195,in build_instance
    obj.pk = Model._default_manager.db_manager(db).get_by_natural_key(*natural_key).pk
  File "/home/parijath/Projects/django_projects/webportal18_multipleapps/parties/models.py",line 17,in get_by_natural_key
    return self.get(name=name,state=state)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/db/models/manager.py",line 127,in manager_method
    return getattr(self.get_queryset(),name)(*args,**kwargs)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/db/models/query.py",line 325,in get
    clone = self.filter(*args,line 679,in filter
    return self._filter_or_exclude(False,*args,line 697,in _filter_or_exclude
    clone.query.add_q(Q(*args,**kwargs))
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/db/models/sql/query.py",line 1310,in add_q
    clause,require_inner = self._add_q(where_part,self.used_aliases)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/db/models/sql/query.py",line 1338,in _add_q
    allow_joins=allow_joins,split_subq=split_subq,File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/db/models/sql/query.py",line 1200,in build_filter
    lookups,value)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/db/models/fields/related.py",line 1761,in get_lookup_constraint
    lookup_class(target.get_col(alias,source),val),AND)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/db/models/lookups.py",line 101,in __init__
    self.rhs = self.get_prep_lookup()
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/db/models/lookups.py",line 139,in get_prep_lookup
    return self.lhs.output_field.get_prep_lookup(self.lookup_name,self.rhs)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/db/models/fields/__init__.py",line 727,in get_prep_lookup
    return self.get_prep_value(value)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/db/models/fields/__init__.py",line 985,in get_prep_value
    return int(value)
ValueError: invalid literal for int() with base 10: 'Andaman and Nicobar'

During handling of the above exception,another exception occurred:

Traceback (most recent call last):
  File "manage.py",line 10,in <module>
    execute_from_command_line(sys.argv)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/core/management/__init__.py",line 354,in execute_from_command_line
    utility.execute()
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/core/management/__init__.py",line 346,in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/core/management/base.py",line 394,in run_from_argv
    self.execute(*args,**cmd_options)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/core/management/base.py",line 445,in execute
    output = self.handle(*args,**options)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/core/management/commands/loaddata.py",line 60,in handle
    self.loaddata(fixture_labels)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/core/management/commands/loaddata.py",line 100,in loaddata
    self.load_label(fixture_label)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/core/management/commands/loaddata.py",line 151,in load_label
    for obj in objects:
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/core/serializers/json.py",line 85,in Deserializer
    six.reraise(DeserializationError,DeserializationError(e),sys.exc_info()[2])
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/utils/six.py",line 685,in reraise
    raise value.with_traceback(tb)
  File "/home/parijath/Projects/virtualenv/django18/lib/python3.4/site-packages/django/core/serializers/json.py",in get_prep_value
    return int(value)
django.core.serializers.base.DeserializationError: Problem installing fixture '/home/parijath/Projects/django_projects/webportal18_multipleapps/parties/fixtures/districts-2.json': invalid literal for int() with base 10: 'Andaman and Nicobar'

我哪里做错了？