在Django中进行多对多过滤

Question

我无法获得此查询以返回多个练习对象，即使我在sql中使用生成的查询，它也按预期返回了两个练习

class Workout(models.Model):
    created = models.DateTimeField(auto_now_add=True)
    workout_type = models.ForeignKey(WorkoutType, on_delete=models.CASCADE)
    exercises = models.ManyToManyField(Exercise, through=u'WorkoutExercise', related_name=u'workout_exercises')


class WorkoutExercise(models.Model):
    exercise = models.ForeignKey(Exercise)
    workout = models.ForeignKey(Workout)

class Exercise(models.Model):
    name = models.CharField(max_length=255, unique=True)

查询是返回每次锻炼以进行最新锻炼

workouts = Workout.objects.latest('created')
    exercises = Exercise.objects.filter(workout_exercises__exact=workouts)

如前所述，这仅在它生成的查询应且在sql中返回2时才返回单个练习。

Answer 1

它应该在没有__exact情况下__exact ：

exercises = Exercise.objects.filter(workout_exercises=workouts)

但是，为什么不直接使用exercises字段：

workout = Workout.objects.latest('created')  # singular sounds more correct to me
exercises = workout.exercises.all()

顺便说一句，这个相关名称令人困惑。 我建议进行workouts或类似方法，因为您是通过exercise.workout_exercises而不是WorkoutExercise实例来管理Workout实例的。