在Django中获取模型的字段 [英] Get model's fields in Django

问题描述

给出一个Django模型，我试图列出所有的字段。我已经看到一些使用_meta模型属性来做这个例子，但是在meta前面没有下划线表示_meta属性是私有属性，不应该被直接访问？ ...因为例如_meta的布局可能会在未来发生变化，而不是稳定的API？ _ / p>

_meta是否为此规则的例外？它是稳定的和准备使用还是被认为是不好的做法访问它？或者是否使用函数或其他方式来内省模型的字段而不使用_meta属性？以下是使用_meta属性

的一些链接列表，任何建议都非常感谢。

django对象获取/设置字段

http://www.djangofoo.com/80/get-list-model-fields

如何内省django模型字段

解决方案

_meta 是私有的，但相对稳定。正在努力使其正式化，记录并删除可能在1.3或1.4之前发生的下划线。我想象会努力确保事情向后兼容，因为很多人一直在使用它。

如果你特别关心兼容性，写一个函数它需要一个模型并返回字段。这意味着如果将来某些事情发生变化，您只需要更改一个功能。

  def get_model_fields（model）：
 return model._meta.fields 
  

我相信这会返回一个字段对象。要从实例中获取每个字段的值，请使用 getattr（instance，field.name）。

更新：Django贡献者正在使用API​​来替换_Meta对象作为Google Summer of Code的一部分。请参阅：

- https://groups.google .com / forum /＃！topic / django-developers / hD4roZq0wyk

- https://code.djangoproject.com/wiki/new_meta_api

Given a Django model, I'm trying to list all of its fields. I've seen some examples of doing this using the _meta model attribute, but doesn't the underscore in front of meta indicate that the _meta attribute is a private attribute and shouldn't be accessed directly? ... Because, for example, the layout of _meta could change in the future and not be a stable API?

Is _meta an exception to this rule? Is it stable and ready to use or is it considered bad practice to access it? Or is there a function or some other way to introspect the fields of a model without using the _meta attribute? Below is a list of some links showing how to do this using the _meta attribute

Any advice is much appreciated.

django object get/set field

http://www.djangofoo.com/80/get-list-model-fields

How to introspect django model fields?

解决方案

_meta is private, but it's relatively stable. There are efforts to formalise it, document it and remove the underscore, which might happen before 1.3 or 1.4. I imagine effort will be made to ensure things are backwards compatible, because lots of people have been using it anyway.

If you're particularly concerned about compatibility, write a function that takes a model and returns the fields. This means if something does change in the future, you only have to change one function.

def get_model_fields(model):
    return model._meta.fields

I believe this will return a list of Field objects. To get the value of each field from the instance, use getattr(instance, field.name).

Update: Django contributors are working on an API to replace the _Meta object as part of a Google Summer of Code. See:
- https://groups.google.com/forum/#!topic/django-developers/hD4roZq0wyk
- https://code.djangoproject.com/wiki/new_meta_api

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