修改django的默认"_id"相关对象的后缀 [英] Modifying django's default "_id" suffix for related objects

问题描述

我正在将django与旧版系统和数据库集成，并具有一个类似于以下的模型

I am integrating django with a legacy system and database and have a model that looks like this

class Label(models.Model)
    iLabelID = models.IntegerField(db_column='LABELID', primary_key=True)
    organization = models.OneToOneField(Organization, related_name='labels', db_column='ORGANIZATION')
    sLabelText = models.CharField(max_length=42)

使用此表示法(或多或少匈牙利表示法)是该项目的要求.

Using this notation (more or less hungarian notation) is a requirement of the project.

以下内容将在Django中工作:

The following will work in django:

>>> Label.objects.get(organization_id=1)

但是我希望能够这样写:

But I want to be able to write this:

>>> Label.objects.get(iOrganizationID=1)

我尝试使用

class MyOneToOneField(models.OneToOneField):
    def get_attname(self):
        # default is:
        # return '%s_id' % self.name
        return 'i%s%sID' % (self.name[0].upper(), self.name[1:])

但这是我在尝试使用它时遇到的错误:

But this is the error I get when trying to use it:

>>> Label.objects.get(iOrganizationID=1)
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "django/db/models/manager.py", line 151, in get
    return self.get_queryset().get(*args, **kwargs)
  File "django/db/models/query.py", line 301, in get
    num = len(clone)
  File "django/db/models/query.py", line 77, in __len__
    self._fetch_all()
  File "django/db/models/query.py", line 854, in _fetch_all
    self._result_cache = list(self.iterator())
  File "django/db/models/query.py", line 230, in iterator
    obj = model(*row_data)
  File "django/db/models/base.py", line 347, in __init__
    setattr(self, field.attname, val)
AttributeError: can't set attribute

这是另一个痛苦点:

我希望生成一些JSON.此JSON将被馈送到我无法控制的系统的另一部分(无法更改名称).我希望我可以执行以下操作:

I wish to generate some JSON. This JSON will be fed to another part of the system on which I have no control (not possible to change names). I wish I could do the following:

json.dumps(list(Label.objects.values('iLabelID', 'iOrganizationID', 'sAnotherValue')))

但这是不可能的.我必须这样做

But this is not possible. I have to do this

list(Label.objects.values('iLabelID', 'organization_id', 'sAnotherValue'))

然后手动将 organization_id 映射到 iOrganizationID ，尽管这对于标签ID来说不是问题.这样会使代码更难维护，更易阅读，并且执行速度较慢.

And then manually map organization_id to iOrganizationID, although this is not a problem for the label's ID. It makes code more difficult to maintain, to read, and slower to execute.

请注意，这不是不是特定于匈牙利符号，您可能需要后缀 _identifier 或 _pk 或其他代替的后缀_id .

Note that this is not specific to hungarian notation, you may need to suffix with _identifier or _pk or whatever instead of _id.

我一定犯了另一个错误，因为正如lanzz指出的，get_attname确实起作用-_-

I must have made another error because as lanzz pointed out get_attname does work -_-

推荐答案

我通过对您的代码进行了一些修改来解决了该问题:

I solved it using some modifications of your code:

class CustomAttrNameForeignKey(djangoFields.related.ForeignKey):
    def __init__(self, *args, **kwargs):
        attname = kwargs.pop('attrname', None)
        super(CustomAttrNameForeignKey, self).__init__(*args, **kwargs)
        self.attname = attname or super(CustomAttrNameForeignKey, self).get_attname()

    def get_attname(self):
        return self.attname

---

class AModelUsingThis(djangoModels.Model):
    snapshot = CustomAttrNameForeignKey(
            ParentalModel, db_column="timestamp", to_field="timestamp",
            attrname='timestamp', related_name="children")

在这种情况下，我们在模型中获得FK的属性，该属性完全没有后缀，但具有给定的名称.我尚未在数据库上对其进行过测试，但只是尝试使用给定的自定义FK实例化模型-效果很好.

In this case we get in the model an attribute for FK with no suffix at all, but with the name given. I haven't tested it yet on DB, but just tried to instantiate model also with this custom FK given -- it works fine.

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