Question

Django Newbie question. I have the following model:

class Leg(models.Model):
  drive_date = models.DateField()
  startpoint = models.CharField(max_length=50)
  endpoint = models.CharField(max_length=50)
  start_time = models.TimeField()
  riders = models.ManyToManyField(Rider, blank=True)
  drivers = models.ManyToManyField(Driver, blank=True)
  carpool = models.ForeignKey(Carpool,  blank=True, null=True)

for certain instances of Leg, I want to remove any existing riders and drivers from the Leg model, but NOT delete them from the Rider or Driver Models (not shown) respectively. Can’t figure out how to do it. When I iterate with:

for driver in leg.drivers.all():
    driver.delete()

It appears to delete the actual Driver object, which I don’t want to do.

Any help is greatly appreciated. Thanks!

Answer 1

One way I might approach this would be to create a custom manager for the Driver model. Untested code below:

from django.db import models

class DriverManager(models.Manager):
    def get_query_set(self):
        return super(DriverManager, self).get_query_set().filter(removed=False)

class Driver(models.Model):
    # new stuff to add ...
    removed = models.BooleanField(default=False)
    objects = models.Manager()  # default manager
    active = DriverManager()  # custom manager

Explanation: A new field, removed, is added to the Driver model. Instead of deleting the record, you set it to True and save. Then, where you would normally filter Driver.objects, use Driver.active instead.