Django自然键的装置给出反序列化错误 [英] Django Natural Key for Fixtures Give Deserialization Error

问题描述

在SO上我看到了一些类似的问题，但似乎没有回答我的特殊问题。我是Django的新手，并按照此页面的指示进行指导允许自己使用自然键加载灯具。然而，我得到了反序列化错误，因为Django想要一个外键的整数，似乎没有将我的自然键映射到一个整数主键，如说明中所述。具体来说，我的相关模型代码是：

I've seen a few similar questions to this on SO, but none seem to answer my particular problem. I'm new to Django and was guiding myself by the instructions at this page to allow myself to use natural keys to load fixtures. Nevertheless, I'm getting Deserialization errors because Django wants an integer for a foreign key and can't seem to map my natural key to an integer primary key as is noted in the instructions. Specifically, my relevant models code is:

class GraphTypeManager(models.Manager):
    def get_by_natural_key(self, type):
        return self.get(type=type)
class GraphType(models.Model):
    type = models.CharField(max_length=100, unique=True)

class GraphManager(models.Manager):
    def get_by_natural_key(self, name):
        return self.get(name=name)
class Graph(models.Model):
    name = models.CharField(max_length=200, unique=True)
    type = models.ForeignKey(GraphType)

class LineManager(models.Manager):
    def get_by_natural_key(self, name):
        return self.get(name=name)
class Line(models.Model):
    name = models.CharField(max_length=200, unique=True)

class GraphToLineManager(models.Manager):
    def get_by_natural_key(self, line, graph):
        return self.get(line=line,graph=graph)
class GraphToLine(models.Model):
    line = models.ForeignKey(Line)
    graph = models.ForeignKey(Graph)
    class Meta:
        unique_together = (('line', "graph"),)

我的YAML夹具是：

- model: graphs_container.GraphType
  pk: null
  fields:
    type: TimeSeries
- model: graphs_container.Graph
  pk: null
  fields:
    name: LikesOverTime
    type: [TimeSeries]
- model: graphs_container.Graph
  pk: null
  fields:
    name: UsersOverTime
    type: [TimeSeries]
- model: graphs_container.Line
  pk: null
  fields:
    name: NumUsers
- model: graphs_container.Line
  pk: null
  fields:
    name: NumLikes

但是当尝试运行 python manage.py loaddata sample_data.yaml ，我收到以下错误：

But when trying to run python manage.py loaddata sample_data.yaml, I get the following error:

DeserializationError: [u"'['TimeSeries']' value must be an integer."]

我做错了什么？

推荐答案

您需要

• 定义 natural_key 模型


• 拥有一个管理员，具有 get_by_natural_key 方法


• 实际附加经理（ objects = GraphManager（））

• define natural_key method in your models
• have a manager with get_by_natural_key method
• actually attach the managers (objects=GraphManager())

播放代码后，我使其工作：

$ b

After playing with your code, I made it work:

class GraphTypeManager(models.Manager):
    def get_by_natural_key(self, type):
        return self.get(type=type)

class GraphType(models.Model):
    type = models.CharField(max_length=100, unique=True)
    objects = GraphTypeManager()

    def natural_key(self):
        return (self.type,)  # must return a tuple

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

class Graph(models.Model):
    name = models.CharField(max_length=200, unique=True)
    type = models.ForeignKey(GraphType)
    objects = GraphManager()

转储数据：

$ bin/django dumpdata index --indent=4 --natural > project/apps/fixtures_dev/initial_data.json
[
    {
        "pk": 1,
        "model": "index.graphtype",
        "fields": {
            "type": "asotuh"
        }
    },
    {
        "pk": 1,
        "model": "index.graph",
        "fields": {
            "type": [
                "asotuh"
            ],
            "name": "saoneuht"
        }
    }
]

bin/django loaddata project/apps/fixtures_dev/initial_data.json 
Installed 2 object(s) from 1 fixture(s)

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