Question

嗨，我有两个后台函数，它们从api获取数据并每隔几秒钟调用.save()来更新模型

这样更新的模型是MBEvent和MBOrders

我想使用外键在模型之间映射数据。 event_id temp_id runner_id是这三个模型的主键。

我想映射 runner_1_back_odds runner_2_back_odds runner_1_lay_odds runner_2_lay_odds从MBEvent以current_back_odds和current_lay_odds到MBBet

我无法获取外键以在Django中工作。我可能会用外键请求什么？我真正想要的是，当MBEvent更新时，数据也将在MBBet中更新。外键是否可以将模型映射在一起并确保数据的完整性？

class MBEvent(models.Model):
     event_id = models.BigIntegerField(primary_key=True)
     event_name = models.CharField(max_length=100,null=True)
     start_time = models.DateTimeField(null=True)
     is_ip = models.CharField(max_length=100,null=True)
     runner_1_name = models.CharField(max_length=100,null=True)
     runner_2_name = models.CharField(max_length=100,null=True)
     runner_1_id = models.BigIntegerField(null=True)
     runner_2_id = models.BigIntegerField(null=True)
     runner_1_back_odds = models.FloatField(null=True)
     runner_2_back_odds = models.FloatField(null=True)
     runner_1_lay_odds = models.FloatField(null=True)
     runner_2_lay_odds = models.FloatField(null=True)

class MBOrders(models.Model):
    temp_id = models.FloatField(primary_key=True)
    event_id = models.BigIntegerField(null=True)
    event_name = models.CharField(null=True,max_length=300)
    runner_name = models.CharField(null=True, max_length=100)
    runner_id = models.BigIntegerField(null=True)
    odds = models.FloatField(null=True)
    remaining = models.IntegerField(null=True)
    pot_pro = models.IntegerField(null= True)
    rem_pot_pro = models.IntegerField(null=True)
    pot_lib = models.IntegerField(null=True)
    side = models.CharField(null=True, max_length=8)
    stake = models.IntegerField(null=True)
    status = models.CharField(null=True, max_length=10)
    time_stamp = models.DateTimeField(null=True)


class MBBet(models.Model):
    runner_id = models.BigIntegerField(primary_key=True)
    runner_name = models.ForigenKey(MBEvent,on_delete=MODELS.CASCADE)
    event_name = models.CharField(null=True,max_length=300)
    current_back_odds = models.ForigenKey(MBEvent,on_delete=MODELS.CASCADE)
    current_lay_odds =  models.ForigenKey(MBEvent,on_delete=MODELS.CASCADE)
    bet_odds = models.FloatField(null=True)
    side = models.CharField(null=True, max_length=8)
    stake = models.IntegerField(null=True)
    status = models.CharField(null=True, max_length=10)
    time_stamp = models.DateTimeField(null=True)

Answer 1

一旦在模型中设置了ForeignKey字段，就可以像这样使用它们：

mb_event_one = MBEvent()
mb_event_two = MBEvent()

mb_bet = MBBet()
mb_bet.current_back_odds = mb_event_one
mb_bet.current_lay_odds = mb_event_two

mb_bet.save()

这样，您可以直接从父级访问子级属性：

mb_bet.current_back_odds.event_id  # == mb_event_one.event_id
mb_bet.current_lay_odds.event_name  # == mb_event_two.event_name

我建议您为ForeignKey字段使用清晰准确的名称。如果您链接一个事件，则最好致电您的字段hosting_event或类似的名称。

编辑：：好的，我知道您要执行的操作。

ForeignKey字段用于将模型链接在一起，而不是字段。您应该这样使用它们：

class MBRunner(models.Model):
    # ...

class MBEvent(models.Model):
    event_id = models.BigIntegerField(primary_key=True)
    runner = models.ForeignKey(MBRunner, on_delete=models.CASCADE)

my_runner = MBRunner()
my_event = MBEvent(runner=my_runner)

这样，您可以访问事件中所有跑步者的属性。

my_event.runner.runner_name  # == my_runner.runner_name

我建议您再次阅读documentation。

将Django模型链接在一起

1 个答案: