Django: querying multiple types of objects - django

Question

I have a fairly basic model that allows users to create posts of different 'types'. There's currently a Text type and a Photo type that inherits from a base 'Post' type.
I'm currently pulling TextPosts and PhotoPosts and chaining the two QuerySets, but this seems like a bad idea.
Is there a way to simply query for both types of posts at once? The reason I'm not using .filter() on Post itself is because I (presumably) don't have any way of getting the TextPost or PhotoPost object from it (or do I?)
PS: Does it make more sense to call it BasePost or Post if I'll never be using Post by itself?
class Post(AutoDateTimeModel):
POST_TYPES = (
# Linkable Social Networks
('TEXT', 'Text'),
('PHOTO', 'Photo'),
('LINK', 'Link'),
)
post_type = models.ForeignKey(ContentType)
user = models.ForeignKey(User, blank=True, null=True)
interests = models.ManyToManyField(Interest, related_name='interests')
class Meta:
app_label = 'posts'
ordering = ('-created_at',)
def save(self, *args, **kwargs):
if not self.pk:
self.post_type = ContentType.objects.get_for_model(type(self))
# import pdb; pdb.set_trace()
super(Post, self).save(*args, **kwargs)
class TextPost(Post):
""" Text post model """
body = models.TextField()
class Meta:
app_label = 'posts'
class PhotoPost(Post):
""" Photo post model. This can contain multiple photos. """
description = models.TextField()
class Meta:
app_label = 'posts'
class Photo(models.Model):
""" Individual image model, used in photo posts. """
caption = models.TextField()
# source_url = models.URLField(blank=True, null=True)
image = ImageField(upload_to=upload_to)
post = models.ForeignKey(PhotoPost, blank=True, null=True, related_name='photos')
user = models.ForeignKey(User, blank=True, null=True, related_name='photos')
class Meta:
app_label = 'posts'
def __unicode__(self):
return 'Photo Object by: ' + str(self.user.get_full_name())

Answer 1

You can use this nice app django-model-utils, using InheritanceManager in your Post class.
A nice example from the docs:
from model_utils.managers import InheritanceManager
class Place(models.Model):
# ...
objects = InheritanceManager()
class Restaurant(Place):
# ...
class Bar(Place):
# ...
nearby_places = Place.objects.filter(location='here').select_subclasses()
for place in nearby_places:
# "place" will automatically be an instance of Place, Restaurant, or Bar
Applying for your situation:
class Post(AutoDateTimeModel):
...
objects = InheritanceManager()
class TextPost(Post):
...
class PhotoPost(Post):
...
And this answers your question: Is there a way to simply query for both types of posts at once?
You can query for posts now, resulting instances of TextPost and Photoposts