如何将数据从一个模型字段处理到另一个模型字段

Question

I have models of Exercise , Training and Workout .

Training contains some exercises ( Exercise )

Workout contains trainings ( Training ).

Snippet of my models.py:

class Exercise(models.Model):
    user = models.ForeignKey(User, related_name='exercises',
                             on_delete=models.CASCADE)
    name = models.CharField(max_length=80)
    description = models.TextField(max_length=300)
    details = models.ManyToManyField(ExerciseDetail, blank=True)
...


class Training(models.Model):
    user = models.ForeignKey(User, related_name='trainings',
                             on_delete=models.CASCADE)
    name = models.CharField(max_length=80)
    description = models.CharField(max_length=250)
    exercises = models.ManyToManyField(Exercise, related_name='trainings',
                                       blank=True)
...


class Workout(models.Model):
    user = models.ForeignKey(User, related_name='workouts',
                             on_delete=models.CASCADE)
    created_at = models.DateTimeField(auto_now=True)
    name = models.CharField(max_length=200)
    description = models.TextField(max_length=400, blank=True)
    trainings = models.ManyToManyField(Training, related_name='workouts',
                                       blank=True)
...

I would like to have possibility to use something like Workout.objects.get(name='workout').exercises.objects.all() to get a list/set of all exercises included in trainings of chosen Workout.

I would also like to have possibility to use exercises`` field with Django Rest Framework to list all exercises, possibly with link to particular Exercise``` model serializer.

Can someone give a hint how can I do that?

Answer 1

You can query this with:

Exercise.objects.filter(
    
)

With the consecutive underscores ( __ ), you thus can look "through" relations.

This will thus return the Exercise s that belong to Training s that belong to Workout s with as name 'Workout' .