Django在创建另一个对象时创建并保存许多模型实例 [英] Django Create and Save Many instances of model when another object are created

问题描述

我正在设计一个国际象棋游戏，我想在新的 ChessParty 开始后用象棋人物（状态模型）初始化字段。

我读到有关重写 save（）模型方法的信息，但是我不知道如何在我的情况下使用它。

我正在阅读有关 post_save 之类的信号，但是我有同样的问题。

I am designing a game of chess and I would like to initialize the fields with chess figures (State model) after the start of a new ChessParty.
I read about overriding the save() model method, but I don't know how to use it in my case.
I am reading about signals like post_save, but I have the same problem.

    def save(self, *args, **kwargs):
        (Here i want create many instances of another Model)
    super(ChessParty, self).save(*args, **kwargs)

这是到目前为止的代码：

And here is my code so far:

class ChessParty(models.Model):
    chessparty_id = models.AutoField("ID partii", primary_key=True)
    arbiter = models.ForeignKey(Arbiter, related_name='sedzia', 
    verbose_name="Sędzia")
    white = models.ForeignKey(Player, related_name='Białe', 
    verbose_name="Białe figury")
    black = models.ForeignKey(Player, related_name='Czarne', 
    verbose_name="Czarne figury")
    tournament = models.ForeignKey(Tournament, verbose_name="Nazwa turnieju")

    def __str__(self):
        return "{white} vs {black}, ({tournament})"\
            .format(black=self.black, white=self.white, tournament=self.tournament)


class OneMove(models.Model):
party = models.ForeignKey(ChessParty, default='0', verbose_name="Partia")
chessman = (
    ('a1_w_rook', 'biała wieża a1'), ('h1_w_rook', 'biała wieża h1'),
    ('b1_w_knight', 'biały skoczek b1'), ('g1_w_knight', 'biały skoczek g1'),
    ('c1_w_bishop', 'biały goniec c1'), ('f1_w_bishop', 'biały goniec f1'),
    ('d1_w_queen', 'biały hetman d1'), ('e1_w_king', 'biały król e1'),
    ('a2_w_pawn', 'biały pion a2'), ('b2_w_pawn', 'biały pion b2'),
    ('c2_w_pawn', 'biały pion c2'), ('d2_w_pawn', 'biały pion d2'),
    ('e2_w_pawn', 'biały pion e2'), ('f2_w_pawn', 'biały pion f2'),
    ('g2_w_pawn', 'biały pion g2'), ('h2_w_pawn', 'biały pion h2'),
    ('a8_b_rook', 'czarna wieża a1'), ('h8_b_rook', 'czarna wieża h8'),
    ('b8_b_knight', 'czarny skoczek b1'), ('g8_b_knight', 'czarny skoczek g8'),
    ('c8_b_knight', 'czarny goniec c1'), ('f8_b_bishop', 'czarny goniec f8'),
    ('d8_b_queen', 'czarny hetman d1'), ('e8_b_king', 'czarny król e8'),
    ('a7_b_pawn', 'czarny pion a7'), ('b7_b_pawn', 'czarny pion b7'),
    ('c7_b_pawn', 'czarny pion c7'), ('d7_b_pawn', 'czarny pion d7'),
    ('e7_b_pawn', 'czarny pion e7'), ('f7_b_pawn', 'czarny pion f7'),
    ('g7_b_pawn', 'czarny pion g7'), ('h7_b_pawn', 'czarny pion h7'),
 )
chessman = models.CharField(max_length=30, choices=chessman, default='pionek', verbose_name="Figura Szachowa")
mymove = []
for a, b in itertools.product('abcdefgh', '12345678'):
    name = a + b
    mymove.append((name, name))
mytuple = tuple(mymove)
move = models.CharField(max_length=2, choices=mytuple, default='a1', verbose_name="Ruch na")

class Meta:
    abstract = True


class State(OneMove):
state_id = models.PositiveIntegerField(default=0, verbose_name="numer ruchu")
is_capture = models.BooleanField(default=False, verbose_name="Czy zbita")
capture_choice = (
    ('true', 'zbity'),
    ('false', 'nie zbity'),
)
is_capture = models.CharField(max_length=9, choices=capture_choice, default='false', verbose_name="Czy zbity")

推荐答案

使用 save（）：

Using save():

如果要使用 save（）方法，您可以执行以下操作：

If you want to use the save() method, you could do the following:

def save(self, *args, **kwargs):
    OtherModel.objects.create(something=kwargs['something'])
    YetAnotherModel.objects.create(
        something_else=kwargs['something_else']
    )
    super(ChessParty, self).save(*args, **kwargs)

如@ e4c5在他的声明中所述评论，它更易于实现，这就是为什么要包含它！

As @e4c5 states in his comment, it is easier to implement and that is why I include it!

我对这个问题的看法：

尽管您可以在 save（）上执行此操作，但我还是建议使用信号。

Although you could do this on the save(), I would recommend instead to use a signal.

具体使用 post_save 信号。操作方法如下：

Specifically use a post_save signal. Here is how to do this:

1. 创建文件 your_app / signals.py ：

from django.db.models.signals import post_save
from django.dispatch import receiver

from your_app.models import ChessParty, OtherModel, YetAnotherModel


@receiver(post_save, sender=ChessParty)
def change_my_name_plz (sender, instance, created, **kwargs):
    if created:
        OtherModel.objects.create(something=kwargs['something'])
        YetAnotherModel.objects.create(
            something_else=kwargs['something_else']
        )

您现在需要覆盖<$ c $在 your_app / app.py 上的c> ready（）函数：

You now need to override the ready() function on your_app/app.py:

from django.apps import AppConfig

class YourAppConfig(AppConfig):
    name = 'your_project.your_app'

    def ready(self):
        import your_project.your_app.signals

最后，在 your_app / __ init __。py 中添加以下内容：

default_app_config = 'your_project.your_app.apps.YourAppConfig'

现在，您将创建一个创建 OtherModel 和的信号在您创建新的 ChessParty 对象之后，即可查看YetAnotherModel 对象。

Now you have a signal that will create an OtherModel and YetAnotherModel objects right after you create a new ChessParty object.

定义信号的另一种方法：

还有一种不使用 @receiver 装饰器，但 connect（） 方法：

There is an alternative way that does not use the @receiver decorator, but the connect() method:

1. your_app / signals.py ：

from your_app.models import ChessParty, OtherModel, YetAnotherModel


def change_my_name_plz (sender, instance, created, **kwargs):
    if created:
        OtherModel.objects.create(something=kwargs['something'])
        YetAnotherModel.objects.create(
            something_else=kwargs['something_else']
        )

your_app / app.py ：

from django.apps import AppConfig
from django.db.models.signals import post_save

from your_app.models import ChessParty
from your_project.your_app.signals import change_my_name_plz

class YourAppConfig(AppConfig):
    name = 'your_project.your_app'

    def ready(self):
        post_save.connect(change_my_name_plz, sender=ChessParty)

your_app / __ init __。py 保持与上述相同（步骤3）。

your_app/__init__.py stays the same as above (step 3).

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