>比赛 – 将处理比赛数据
>条目 – 将处理与参赛者进入比赛相关的功能
在比赛应用程序中,我有一个模型代表比赛的一部分：
class Division(models.Model):
competition = models.ForeignKey(Competition)
discipline = models.CharField(max_length=1,choices=DISCIPLINE_CHOICES)
age_group = models.ForeignKey(AgeGroup)
participants = models.ManyToManyField(Competitor,through='Entry')
我想将Entry模型放入条目应用程序中：
class Entry(models.Model):
division = models.ForeignKey('Division')
competitor = models.ForeignKey(Competitor)
withdrawn = models.BooleanField(default=False)
如何解决from … import …语句,以便它们有效？当我输入import语句时,例如来自entries.models import Entry我从syncdb忽略这些应用程序的模型(因为导入是循环的)或当我删除其中一个或两个时,我得到验证错误：
Error: One or more models did not
validate: entries.entry: ‘division’
has a relation with model Division,
which has either not been installed or
is abstract. competitions.division:
‘participants’ specifies an m2m
relation through model Entry,which
has not been installed
我理解为什么会发生这种情况,但我不知道如何更改它,以便它可以工作(不需要将Entry模型移动到竞赛应用程序中,我真的不想这样做).
解决方法
Django documentation on the ForeignKey class说：
To refer to models defined in another
application,you can explicitly
specify a model with the full
application label. For example,if the
Manufacturer model above is defined in
another application called production,
you’d need to use:
class Car(models.Model):
manufacturer = models.ForeignKey('production.Manufacturer')
This sort of reference can be useful when resolving circular import dependencies between two applications.