我需要在不使用主键的情况下转储和加载模型对象的夹具。模型扁平。我知道Django中的自然键，花了很多时间阅读文档，但所有文档都只有使用自然键而不是关系（fk / m2m）的解决方案。这完全不是我需要的。
我需要这样的东西：
（models.py）
class Template(models.Model):
name = models.CharField(_('name'), max_length=100)
content = models.TextField(_('content'), blank=True)
def natural_key(self):
return (self.name,)
（fixture1.json）
[
{
"pk": null,
"model": "dbtemplates.Template",
"fields" {
"content": "",
"name": "product"
}
}
]
并在命令之后
./manage.py <SOME_LOADDATA_COMMAND> fixture1.json --natural
我需要更新名为＆＃34; product＆＃34;的模板对象。或者插入它。
标准的Django命令不会这样做。请帮助我解决任何问题。也许这有一些库？我很困惑。
Django 1.6。 Python 2.7
答案 0 :(得分：3)
Django 1.6没有提供使用自然主键转储数据的方法，但是Django 1.7可以。
--natural-primary选项）：https://docs.djangoproject.com/en/1.7/ref/django-admin/#dumpdata-app-label-app-label-app-label-model 不幸的是，基本Django 1.6序列化程序不支持use_natural_primary_keys关键字参数：https://github.com/django/django/blob/1.6.11/django/core/serializers/base.py#L20
所以我建议你升级到django 1.7（我完全理解并不总是这样）或者你编写自己的序列化器，从基础Django 1.7序列化器（https://github.com/django/django/blob/1.7.11/django/core/serializers/base.py）中汲取灵感。
答案 1 :(得分：0)
基于answer of régis-b我编写了一些允许在Django 1.6＆＃34; loaddata＆＃34;中使用自然键的代码。管理命令，无需升级到1.7 。我选择这种方式是因为我的项目的全面升级可能会很痛苦。这个解决方案可以被认为是暂时的。
树形结构：
├── project_main_app
│ ├── __init__.py
│ ├── backports
│ │ ├── __init__.py
│ │ └── django
│ │ ├── __init__.py
│ │ └── deserializer.py
│ └── monkey.py
<强> project_main_app /反向移植/ django的/ deserializer.py
from __future__ import unicode_literals
from django.conf import settings
from django.core.serializers import base
from django.core.serializers.python import _get_model
from django.db import models, DEFAULT_DB_ALIAS
from django.utils.encoding import smart_text
from django.utils import six
def Deserializer(object_list, **options):
"""
Deserialize simple Python objects back into Django ORM instances.
It's expected that you pass the Python objects themselves (instead of a
stream or a string) to the constructor
"""
db = options.pop('using', DEFAULT_DB_ALIAS)
ignore = options.pop('ignorenonexistent', False)
models.get_apps()
for d in object_list:
# Look up the model and starting build a dict of data for it.
Model = _get_model(d["model"])
data = {Model._meta.pk.attname: Model._meta.pk.to_python(d.get("pk", None))}
m2m_data = {}
model_fields = Model._meta.get_all_field_names()
# Handle each field
for (field_name, field_value) in six.iteritems(d["fields"]):
if ignore and field_name not in model_fields:
# skip fields no longer on model
continue
if isinstance(field_value, str):
field_value = smart_text(field_value, options.get("encoding", settings.DEFAULT_CHARSET), strings_only=True)
field = Model._meta.get_field(field_name)
# Handle M2M relations
if field.rel and isinstance(field.rel, models.ManyToManyRel):
if hasattr(field.rel.to._default_manager, 'get_by_natural_key'):
def m2m_convert(value):
if hasattr(value, '__iter__') and not isinstance(value, six.text_type):
return field.rel.to._default_manager.db_manager(db).get_by_natural_key(*value).pk
else:
return smart_text(field.rel.to._meta.pk.to_python(value))
else:
m2m_convert = lambda v: smart_text(field.rel.to._meta.pk.to_python(v))
m2m_data[field.name] = [m2m_convert(pk) for pk in field_value]
# Handle FK fields
elif field.rel and isinstance(field.rel, models.ManyToOneRel):
if field_value is not None:
if hasattr(field.rel.to._default_manager, 'get_by_natural_key'):
if hasattr(field_value, '__iter__') and not isinstance(field_value, six.text_type):
obj = field.rel.to._default_manager.db_manager(db).get_by_natural_key(*field_value)
value = getattr(obj, field.rel.field_name)
# If this is a natural foreign key to an object that
# has a FK/O2O as the foreign key, use the FK value
if field.rel.to._meta.pk.rel:
value = value.pk
else:
value = field.rel.to._meta.get_field(field.rel.field_name).to_python(field_value)
data[field.attname] = value
else:
data[field.attname] = field.rel.to._meta.get_field(field.rel.field_name).to_python(field_value)
else:
data[field.attname] = None
# Handle all other fields
else:
data[field.name] = field.to_python(field_value)
# The key block taken from Django 1.7 sources
obj = build_instance(Model, data, db)
yield base.DeserializedObject(obj, m2m_data)
# This is also taken from Django 1.7 sources
def build_instance(Model, data, db):
"""
Build a model instance.
If the model instance doesn't have a primary key and the model supports
natural keys, try to retrieve it from the database.
"""
obj = Model(**data)
if (obj.pk is None and hasattr(Model, 'natural_key') and
hasattr(Model._default_manager, 'get_by_natural_key')):
natural_key = obj.natural_key()
try:
obj.pk = Model._default_manager.db_manager(db).get_by_natural_key(*natural_key).pk
except Model.DoesNotExist:
pass
return obj
<强> project_main_app / monkey.py
def patch_all():
import django.core.serializers.python
import project_main_app.backports.django.deserializer
# Patch the Deserializer
django.core.serializers.python.Deserializer = project_main_app.backports.django.deserializer.Deserializer
<强> project_main_app / init.py
from project_main_app.monkey import patch_all
patch_all()
所以在此之后我只添加一些东西，我的模型变得像
class TemplateManager(models.Manager):
"""1"""
def get_by_natural_key(self, name):
return self.get(name=name)
class Template(models.Model):
name = models.CharField(_('name'), max_length=100)
content = models.TextField(_('content'), blank=True)
objects = TemplateManager() # 2
def natural_key(self):
"""3"""
return (self.name,)
如果灯具有像
那样的空白pk[
{
"pk": null,
"model": "dbtemplates.Template",
"fields": {
"content": "Some content",
"name": "product"
}
}
]
标准命令 ./ manage.py loaddata dbtemplates.Template 通过名称字段更新或插入对象匹配。
警告：所有自然关键组件（例如＆＃34;名称＆＃34;在我的情况下）都必须在数据库中具有唯一值。正确的方法是通过添加参数＆＃34; unique = True＆＃34;来设置它们的唯一性。在定义模型时。