如何在Django中更新模型对象？ [英] How to update model object in django?

问题描述

我正在使用以下代码更新状态。

I am using below code for update the status.

current_challenge = UserChallengeSummary.objects.filter(user_challenge_id=user_challenge_id).latest('id')
current_challenge.update(status=str(request.data['status']))

我遇到以下错误：

'UserChallengeSummary'对象没有属性'update'

'UserChallengeSummary' object has no attribute 'update'

要解决此错误：
我找到了解决方案：

For solve this error: I found solutions:

current_challenge.status = str(request.data['status'])
current_challenge.save()

还有其他更新记录的方法吗？

Is there any another way to update record?

推荐答案

您的工作解决方案是通常使用的方法

Your working solution is the way usually used in Django, as @Compadre already said.

但是有时候（例如，在测试中）能够一次更新多个字段很有用。对于这种情况，我编写了简单的帮助程序：

But sometimes (for example, in tests) it's useful to be able to update multiple fields at once. For such cases I've written simple helper:

def update_attrs(instance, **kwargs):
    """ Updates model instance attributes and saves the instance
    :param instance: any Model instance
    :param kwargs: dict with attributes
    :return: updated instance, reloaded from database
    """
    instance_pk = instance.pk
    for key, value in kwargs.items():
        if hasattr(instance, key):
            setattr(instance, key, value)
        else:
            raise KeyError("Failed to update non existing attribute {}.{}".format(
                instance.__class__.__name__, key
            ))
    instance.save(force_update=True)
    return instance.__class__.objects.get(pk=instance_pk)

用法示例：

current_challenge = update_attrs(current_challenge, 
                                 status=str(request.data['status']),
                                 other_field=other_value)
                                 # ... etc.

如果有，可以删除 instance.save（）从函数（在函数调用后显式调用）。

If you with, you can remove instance.save() from the function (to call it explicit after the function call).

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