Django - 将多个外键用于同一型号 [英] Django - using multiple foreign key to the same model

问题描述

我试图在同一模型中使用相同的外键两个字段，并且收到错误。

我试图拥有一个主要和次要的调用用户，但不知道如何在收到以下错误之后格式化关系。

  class ManualRotas（models.Model）：
 rota_name = models.CharField（max_length = 200，choices = settings.ONCALL_ROTAS）
 primary_user = models.ForeignKey（User，unique = True，verbose_name =Primary OnCall Engineer）
 p_start_time = models .DateTimeField（verbose_name =开始时间）
 p_end_time = models.DateTimeField（verbose_name =结束时间）
 secondary_user = models.ForeignKey（User，verbose_name =Backup OnCall Engineer，unique = True ，blank = True，null = True）
 s_start_time = models.DateTimeField（blank = True，null = True，verbose_name =开始时间）
 s_end_time = models.DateTimeField（blank = True，null = True，verbose_name =开始时间）
 
 
错误：
 oncall.ManualRotas.p rimary_user：（fields.E304）ManualRotas.primary_user的反向访问者与ManualRotas.secondary_user的反向访问者冲突。 
提示：添加或更改一个related_name参数到ManualRotas.primary_user或ManualRotas.secondary_user的定义。 
 oncall.ManualRotas.secondary_user：（fields.E304）ManualRotas.secondary_user的反向访问者与ManualRotas.primary_user的反向访问者冲突。 
提示：将相关名称参数添加或更改为ManualRotas.secondary_user或ManualRotas.primary_user的定义。 
 
警告：
 oncall.ManualRotas.primary_user：（fields.W342）在ForeignKey上设置unique = True与使用OneToOneField具有相同的效果。 
提示：ForeignKey（unique = True）通常由OneToOneField更好地服务。 
 oncall.ManualRotas.secondary_user：（fields.W342）在外键上设置unique = True与使用OneToOneField的效果相同。 
提示：ForeignKey（unique = True）通常由OneToOneField更好地服务。 
 
系统检查确定了4个问题（0个静音）。 
  

解决方案

你必须定义不同的 related_name 到 ForeignKeys 列。例如：

 类ManualRotas（models.Model）：
 primary_user = models.ForeignKey（User，related_name =' related_primary_manual_roats'，unique = True，verbose_name =Primary OnCall Engineer）
＃相关名称^ v 
 secondary_user = models.ForeignKey（User，related_name ='related_secondary_manual_roats'，verbose_name =Backup OnCall Engineer unique = True，blank = True，null = True）
＃....其他列
  

< hr>

另请参阅 ForeignKey.related_name 文档，其中说：

用于从相关对象返回到此关系的关系的名称。它也是 related_query_name （目标模型中用于反向过滤器名称的名称）的默认值。请参阅相关对象文档以获得完整的说明和示例。注意，当在抽象模型上定义关系时，必须设置此值;当你这样做时，可以使用一些特殊的语法。

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相关文章： p>

• Django：外键冲突的反向访问者




• Django反向访问者冲突

I'm trying to use the same foreign key for two fields in the same model and am getting an error.

Im trying to have a primary and secondary on call user, but am not sure how to format the relationship after receiving the errors below

class ManualRotas(models.Model):
    rota_name = models.CharField(max_length=200,choices=settings.ONCALL_ROTAS)
    primary_user = models.ForeignKey(User, unique=True, verbose_name="Primary OnCall Engineer")
    p_start_time = models.DateTimeField(verbose_name="Start Time")
    p_end_time = models.DateTimeField(verbose_name="End Time")
    secondary_user = models.ForeignKey(User, verbose_name="Backup OnCall Engineer", unique=True,blank=True,null=True)
    s_start_time = models.DateTimeField(blank=True,null=True, verbose_name="Start Time")
    s_end_time = models.DateTimeField(blank=True,null=True,verbose_name="Start Time")


ERRORS:
oncall.ManualRotas.primary_user: (fields.E304) Reverse accessor for 'ManualRotas.primary_user' clashes with reverse accessor for 'ManualRotas.secondary_user'.
        HINT: Add or change a related_name argument to the definition for 'ManualRotas.primary_user' or 'ManualRotas.secondary_user'.
oncall.ManualRotas.secondary_user: (fields.E304) Reverse accessor for 'ManualRotas.secondary_user' clashes with reverse accessor for 'ManualRotas.primary_user'.
        HINT: Add or change a related_name argument to the definition for 'ManualRotas.secondary_user' or 'ManualRotas.primary_user'.

WARNINGS:
oncall.ManualRotas.primary_user: (fields.W342) Setting unique=True on a ForeignKey has the same effect as using a OneToOneField.
        HINT: ForeignKey(unique=True) is usually better served by a OneToOneField.
oncall.ManualRotas.secondary_user: (fields.W342) Setting unique=True on a ForeignKey has the same effect as using a OneToOneField.
        HINT: ForeignKey(unique=True) is usually better served by a OneToOneField.

System check identified 4 issues (0 silenced).

解决方案

You have to define different related_name to both the ForeignKeys columns. For example:

class ManualRotas(models.Model):
    primary_user = models.ForeignKey(User, related_name='related_primary_manual_roats', unique=True, verbose_name="Primary OnCall Engineer")
    #                            related names ^ v
    secondary_user = models.ForeignKey(User, related_name='related_secondary_manual_roats', verbose_name="Backup OnCall Engineer", unique=True,blank=True,null=True)
    # .... Other columns

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Please also refer ForeignKey.related_name document, which says:

The name to use for the relation from the related object back to this one. It’s also the default value for related_query_name (the name to use for the reverse filter name from the target model). See the related objects documentation for a full explanation and example. Note that you must set this value when defining relations on abstract models; and when you do so some special syntax is available.

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