Django循环模型参考 [英] Django circular model reference

问题描述

我开始在一个小型的足球联赛管理网站上工作（主要是为了学习目的），并且不能围绕着Django车型的关系。为了简单起见，假设我有两种类型的对象 - 玩家和团队。当然，一个球员属于一个球队，所以在球员模型中是一个ForeignKey（Team）。
所以我去：

  class Team（models.Model）：
 name = models.CharField ）
 class Player（models.Model）：
 name = models.CharField（）
 team = models.ForeignKey（Team）
  

然后，我希望每个队伍都有一个队长，这将是球队的一个球员，所以在Team模型中将是一个ForeignKey（Player）。但这将创造一个循环依赖。
授予我的Django经验是有限的，但它似乎是一个简单的问题，虽然我无法弄清楚我在概念上做错了什么。

解决方案

这是解决这个问题的另一种方法。
我创建了一个额外的表来存储玩家和团队之间的关系，而不是创建循环依赖。所以最终看起来像这样：

  class Team（Model）：
 name = CharField（max_length = 50 ）
 
 def get_captain（self）：
返回PlayerRole.objects.get（team = self）.player 
 
类玩家（模型）：
 first_name = CharField（max_length = 50）
 last_name = CharField（max_length = 50，blank = True）
 
 def get_team（self）：
返回PlayerRole.objects.get = b 
 PLAYER_ROLES =（
（Regular，Regular），
（Captain，Captain）
）
 
 class PlayerRole（Model）：
 player = OneToOneField（Player，primary_key = True）
 team = ForeignKey（Team，null = True）
 role = CharField（max_length = 20，choices = PLAYER_ROLES，default = PLAYER_ROLES [0] [0]）
 class Meta：
 unique_together =（player，team）
  / pre> 
 
 
在存储方面的效率可能略低于建议的解决方法，但它避免了循环微小的依赖性，并保持数据库结构的清晰和清晰。 
欢迎评论。
 
I'm starting to work on a small soccer league management website (mostly for learning purposes) and can't wrap my mind around a Django models relationship. For simplicity, let's say I have 2 types of objects - Player and Team. Naturally, a player belongs to one team so that's a ForeignKey(Team) in the Player model.
So I go:
class Team(models.Model):
    name = models.CharField()
class Player(models.Model):
    name = models.CharField()
    team = models.ForeignKey(Team)
Then I want each team to have a captain which would be one of the players so that would be a ForeignKey(Player) in the Team model. But that would create a circular dependency. 
Granted my Django experience is limited, but it seems like a simple problem, though I can't figure out what I'm doing wrong conceptually. 
解决方案
Here is another way to tackle this problem.
Instead of creating a circular dependency, I created an additional table that stores the relationship between players and teams. So in the end it looks like this:
class Team(Model):
    name = CharField(max_length=50)

    def get_captain(self):
        return PlayerRole.objects.get(team=self).player

class Player(Model):
    first_name = CharField(max_length=50)
    last_name = CharField(max_length=50, blank=True)

    def get_team(self):
        return PlayerRole.objects.get(player=self).team

PLAYER_ROLES = (
    ("Regular", "Regular"),
    ("Captain", "Captain")
    )

class PlayerRole(Model):
    player = OneToOneField(Player, primary_key=True)
    team = ForeignKey(Team, null=True)
    role = CharField(max_length=20, choices=PLAYER_ROLES, default=PLAYER_ROLES[0][0])
    class Meta:
        unique_together = ("player", "team")
It might be slightly less efficient in terms of storage than the suggested workaround, but it avoids the circular dependency and keeps the DB structure clean and clear. 
Comments are welcome.

                        
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