使用Django F()对象更新多列 [英] Update multiple columns using django F() object

问题描述

我有一个模型，该模型以每列一个整数统计信息的形式存储统计信息.我有一个可以处理上述统计信息的视图，如下所示:

I have a model that stores stats on a one integer stat per column basis. I have a view that handles the update of said stats, like so:

class PlayerStats(models.Model):
    #In game stats - these represent the actual keys sent by the game
    NumberOfJumps = models.IntegerField(default=0)
    NumberOfDoubleJumps = models.IntegerField(default=0)
    NumberOfSilverPickups = models.IntegerField(default=0)
    NumberOfGoldPickups = models.IntegerField(default=0)
    NumberOfHealthPickups = models.IntegerField(default=0)

我基本上得到了一个统计数字，需要添加到数据库中存储的当前统计信息中.

I basically get a dicitonary of stats that I need to to add to the current stats stored in the database.

我真的不想从模型中提取所有数据，然后再次对其进行更新，因为如果可能的话，我想在数据库级别执行此操作.

I really don´t want to pull all of the data out of the model and then update it again, as I would like to do this on the database level, if possible.

一位同事建议我使用django的F()对象将其从视图代码中推出，主要是为了使其保持线程安全并避免任何mysql死锁(状态表可能会不断更新通过不同的线程

A colleague suggested that I use django´s F() object in order to push this out of the view code, mostly in order to keep it thread-safe and avoid any mysql deadlocks (the stats table is potentially being updated continually by different threads)

该词典包含与数据库中使用的那些键相同的键，因此目前，我正在这样做:

The dictionary contains keys that mirror those used in the database, so at the moment I´m doing it like this:

def update_stats(new_stats):
    player_stats = PlayerStats(user=user, **new_stats)
    old_stats = player_stats.values()[0]
    updated_stats = {}
    for stat in new_stats:
        if old_stat[stat]:
            updated_stats[stat] = old_stats[stat] + new_stats[stat]
    PlayerStats.objects.filter(user=user).update(**updated_stats)

有人知道如何使用F()对象实现此目标吗?

Anybody have any pointers as to how to achieve this by using the F() object?

推荐答案

要使用 models.F 更新，您需要构建类似

To update using models.F, you need to construct something like

qs.update(field_1=models.F('field_1')+field_1_delta,
          field_2=models.F('field_2')+field_2_delta, 
          ...)

对于您的代码，可能是

new_stats = {
    'NumberOfHealthPickups': 99
    # ...
}
updated_stats = {}
for stat in new_stats:
    updated_stats[stat] = models.F(stat) + new_stats[stat]
PlayerStats.objects.filter(user=user).update(**updated_stats)

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