如何更新django模型实例的多个字段？ [英] How to update multiple fields of a django model instance?

问题描述

我想知道，在django中更新模型实例的多个字段的标准方法是什么？ ...如果我有一些字段的模型，

 类foomodel（models.Model）：
 field1 = models.CharField（max_length = 10）
 field2 = models.CharField（max_length = 10）
 field3 = models.CharField（max_length = 10）
 ... 
  

...我用一个字段给出了实例化，然后在另一个步骤中，我想提供其余的字段，只需传递一个字典或键值参数，我该怎么办？可以吗？

换句话说，说我有一个字典，其中有一些数据，它有我想要写入该模型的一个实例的一切。模型实例已经在一个单独的步骤中被实例化，并且假设它还没有被持久化。我可以为每个字段说 foo_instance.field1 = my_data_dict ['field1'] ，但有些东西告诉我应该有一种方法来调用模型实例上的方法，一次传递所有的字段值对，并更新它们。像 foo_instance.update（my_data_dict）。我没有看到任何这样的内置方法，我错过了，还是有效地完成了？

我有一种感觉这是一个明显的RTM类型的问题，但我没有在文档中看到它。

解决方案

很有可能混淆 __ dict __ ，但这不适用于从父类继承的属性。 / p>

您可以对dict进行迭代，以分配给对象：

  for（key，value）in my_data_dict.items（）：
 setattr（obj，key，value）
  

或者您可以直接从查询集修改它（确保您的查询集仅返回您感兴趣的对象）：

 code> FooModel.objects.filter（whatever =anything）。update（** my_data_dict）
  

I'm wondering, what is a standard way of updating multiple fields of an instance of a model in django? ... If I have a model with some fields,

Class foomodel(models.Model):
    field1 = models.CharField(max_length=10)
    field2 = models.CharField(max_length=10)
    field3 = models.CharField(max_length=10)
    ...

... and I instantiate it with one field given, and then in a separate step I want to provide the rest of the fields, how do I do that by just passing a dictionary or key value params? Possible?

In other words, say I have a dictionary with some data in it that has everything I want to write into an instance of that model. The model instance has been instantiated in a separate step and let's say it hasn't been persisted yet. I can say foo_instance.field1 = my_data_dict['field1'] for each field, but something tells me there should be a way of calling a method on the model instance where I just pass all of the field-value pairs at once and it updates them. Something like foo_instance.update(my_data_dict). I don't see any built-in methods like this, am I missing it or how is this efficiently done?

I have a feeling this is an obvious, RTM kind of question but I just haven't seen it in the docs.

解决方案

It's tempting to mess with __dict__, but that won't apply to attributes inherited from a parent class.

You can either iterate over the dict to assign to the object:

for (key, value) in my_data_dict.items():
    setattr(obj, key, value)

Or you can directly modify it from a queryset (making sure your query set only returns the object you're interested in):

FooModel.objects.filter(whatever="anything").update(**my_data_dict)

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