如何在Django模型中存储ForeignKey列表?

Question

我正在构建一个用户可以购买球员的平台(就像在幻想联赛中一样)。所以我有4个模型:

POSITION_CHOICES = ((1,'1'),
                    (2,'2'),
                    (3,'3'),
                    (4,'4'),
                    (5,'5'),
)
class Team(models.Model):
    ...
class Player(models.Model):
    team = models.ForeignKey(Team, blank=True, null=True, ...)
    position = MultiSelectField(
    user = models.ForeignKey(User, unique=True)
    player1 = models.ForeignKey(Player, related_name='+', blank=True,null=True,
                                limit_choices_to={'position__icontains':1},...)
    player2 = ...
    player3 = ...
    player4 = ...
    player5 = ...
    ...
class FantasyTeams(models.Model):
    user = models.ForeignKey(User, unique=True)
    team1 = models.ForeignKey(Team, verbose_name='Team', blank=True, null=True,
                              on_delete=models.SET_NULL)
    ...

基本上一个Team包含0个或多个Players。FantasyPlayers和FantasyTeams都是用户购买的球员和球队(他可以购买0到5名球员和0到1支球队，但这些数字可能会改变)。全局最我目前的方法是相当丑陋的，即使它工作。我现在正在寻找更整洁的东西(因为我发现这根本不是通用的)，比如用players替换player#字段，其中包含ForeignKey列表。我也愿意将FantasyPlayers和FantasyTeams这两个模型合并为一个包含玩家列表的模型。5)，团队列表(最多5个)。1)和ForeignKey给它的用户。

我看到一对多字段在看类似的问题时被提到了几次，但它所做的只是让我更加困惑于OneToOneField和ManyToManyField。

是否有任何方向你可以给我存储在Django模型的ForeignKey列表?

---

解决方案

替换之前的FantasyPlayers和FantasyTeams:

class FantasyTeam(models.Model):
    user = models.ForeignKey(User, unique=True)
    players = models.ManyToManyField(Player, blank=True, null=True)
    teams = models.ManyToManyField(Team, blank=True, null=True)
    ...

这是我现在如何创建和保存模型(通过ModelForm):

def fantasy_create(request):
    # Handling form datas
    if request.method == "POST":
        form = EditFantasyTeamForm(request.POST)
        if form.is_valid():
            fantasy = FantasyTeam.objects.create(user=request.user)
            for player in form.cleaned_data['players']:
                fantasy.players.add(player)
            for team in form.cleaned_data['teams']:
                fantasy.teams.add(team)
            return redirect(...)
    # Form is not submitted yet
    else:
        form = EditFantasyTeamForm()
    return render_to_response(...)

def fantasy_edit(request):
    # Fetching the FantasyTeam object
    fantasy = ...
    # Handling form datas
    if request.method == "POST":
        form = EditFantasyTeamForm(request.POST, instance=fantasy)
        if form.isLUTION_valid():
            form.save()
        return redirect(...)
    # Form not submitted yet
    else:
        form = EditFantasyTeamForm(instance=fantasy)
    return render_to_response(...)choices=POSITION_CHOICES, max_length=10)
    ...
class FantasyPlayers(models.Model):
    user = models.ForeignKey(User, unique=True)
    player1 = models.ForeignKey(Player, related_name='+', blank=True,null=True,
                                limit_choices_to={'position__icontains':1},...)
    player2 = ...
    player3 = ...
    player4 = ...
    player5 = ...
    ...
class FantasyTeams(models.Model):
    user = models.ForeignKey(User, unique=True)
    team1 = models.ForeignKey(Team, verbose_name='Team', blank=True, null=True,
                              on_delete=models.SET_NULL)
    ...

基本上一个Team包含0个或多个Players。FantasyPlayers和FantasyTeams都是用户购买的球员和球队(他可以购买0到5名球员和0到1支球队，但这些数字可能会改变)。全局最我目前的方法是相当丑陋的，即使它工作。我现在正在寻找一些更整洁的东西(因为我根本不觉得这是通用的)，比如用players替换player#字段，其中包含ForeignKey列表。我也愿意将FantasyPlayers和FantasyTeams这两个模型合并为一个包含玩家列表的模型。5)，团队列表(最多5个)。1)和ForeignKey的用户。

我看到一对多字段在看类似的问题时被提到了几次，但它所做的只是让我更加困惑于OneToOneField和ManyToManyField。

是否有任何方向你可以给我存储在Django模型的ForeignKey列表?

---

解决方案

替换之前的FantasyPlayers和FantasyTeams:

class FantasyTeam(models.Model):
    user = models.ForeignKey(User, unique=True)
    players = models.ManyToManyField(Player, blank=True, null=True)
    teams = models.ManyToManyField(Team, blank=True, null=True)
    ...

这就是我现在如何创建和保存模型(通过ModelForm):

def fantasy_create(request):
    # Handling form datas
    if request.method == "POST":
        form = EditFantasyTeamForm(request.POST)
        if form.is_valid():
            fantasy = FantasyTeam.objects.create(user=request.user)
            for player in form.cleaned_data['players']:
                fantasy.players.add(player)
            for team in form.cleaned_data['teams']:
                fantasy.teams.add(team)
            return redirect(...)
    # Form is not submitted yet
    else:
        form = EditFantasyTeamForm()
    return render_to_response(...)

def fantasy_edit(request):
    # Fetching the FantasyTeam object
    fantasy = ...
    # Handling form datas
    if request.method == "POST":
        form = EditFantasyTeamForm(request.POST, instance=fantasy)
        if form.isLUTION_valid():
            form.save()
        return redirect(...)
    # Form not submitted yet
    else:
        form = EditFantasyTeamForm(instance=fantasy)
    return render_to_response(...)

Answer 1

您应该使用ManyToManyField

players = models.ManyToManyField(Player, ...)

但这是ok的，只有当一个Player实例可以属于几个FantasyPlayers实例(Team同样的事情)，如果一个Player实例只能属于一个FantasyPlayers实例，你应该颠倒关系，把ForeignKey字段放在Player模型中的FantasyPlayers，然后你可以使用related_field从FantasyPlayers实例访问Player实例的列表。

Answer 2

这个解决方案怎么样?(我不确定ManyToManyField是最好的选择。)

class FantasyPlayer(models.Model):
    user = models.ForeignKey(User, unique=True)
    player = models.ForeignKey(Player)
    position = models.MultiSelectField(choices=POSITION_CHOICES, max_length=10)
# To get a list of players
user_fantasy_players = user.fantasyplayer_set.all()

它的一个缺点是无法使用limit_choices_to只允许在编辑FantasyPlayer时选择具有匹配位置的Player(如您的示例)，但这可以通过另一种方式解决。在我看来，从长远来看，拥有更优雅、更合理的数据架构更为重要。