Django one to many get all underlying records

问题

I'am creating a django application with a database including the following tables:

I created the models as following:

class Group(models.Model):
    id = models.AutoField(primary_key=True, editable=False)
    text = models.CharField(db_column='Text', max_length=4000)

    class Meta:
        db_table = 'Group'


class Filters(models.Model):
    id = models.AutoField(primary_key=True, editable=False)
    text = models.CharField(db_column='Text', max_length=4000)
    group_id = models.ForeignKey(Group, on_delete=models.CASCADE,
                                 db_column='GroupId')

    class Meta:
        db_table = 'Filters'

The goal is to call an endpoint and return a list with all Groups and underlying Filters. Is it possible to achieve this? If possible, I want it in a Serializer class.

I know I can get the group of a filter record, but is this also possible the otherway around?

回答1:

class Group(models.Model):
    id = models.AutoField(primary_key=True, editable=False)
    text = models.CharField(db_column='Text', max_length=4000)

    class Meta:
        db_table = 'Group'


class Filters(models.Model):
    id = models.AutoField(primary_key=True, editable=False)
    text = models.CharField(db_column='Text', max_length=4000)
    group = models.ForeignKey(Group, on_delete=models.CASCADE,
                                 db_column='GroupId', related_name='filters') # not group_id

This just says, Filters has .group but a group has .filters (related_name), If you didn't specify a related_name, It will be model_qs by default, so it should be filters_qs.

Some additional notes

• Class names should be singular

• Django creates plural names by adding 's', In your case it will create filterss and you'll have to specify a verbose_name_plural (more useless code)

• You don't need to specify db data, column names or whatever unless you're re-creating a backend that already exists or something that needs that.

• It's group and not group_id, We all know that in SQL it's the group_id, however, This is python and you have access to the whole group instance then you instance.id or instance.pk to get it.

来源：https://stackoverflow.com/questions/61481929/django-one-to-many-get-all-underlying-records