django join-like expansion of queryset
- by jimbob
I have a list of Persons each which have multiple fields that I usually filter what's upon, using the object_list generic view. Each person can have multiple Comments attached to them, each with a datetime and a text string. What I ultimately want to do is have the option to filter comments based on dates.
class Person(models.Model):
name = models.CharField("Name", max_length=30)
## has ~30 other fields, usually filtered on as well
class Comment(models.Model):
date = models.DateTimeField()
person = models.ForeignKey(Person)
comment = models.TextField("Comment Text", max_length=1023)
What I want to do is get a queryset like
Person.objects.filter(comment__date__gt=date(2011,1,1)).order_by('comment__date')
send that queryset to object_list and be able to only see the comments ordered by date with only so many objects on a page.
E.g., if "Person A" has comments 12/3/11, 1/2/11, 1/5/11, "Person B" has no comments, and person C has a comment on 1/3, I would see:
"Person A", 1/2 - comment
"Person C", 1/3 - comment
"Person A", 1/5 - comment
I would strongly prefer not to have to switch to filtering based on Comments.objects.filter(), as that would make me have to largely repeat large sections of code in the both the view and template.
Right now if I tried executing the following command, I will get a queryset returning (PersonA, PersonC, PersonA), but if I try rendering that in a template each persons comment_set will contain all their comments even if they aren't in the date range.
Ideally they're would be some sort of functionality where I could expand out a Person queryset's comment_set into a larger queryset that can be sorted and ordered based on the comment and put into a object_list generic view. This normally is fairly simple to do in SQL with a JOIN, but I don't want to abandon the ORM, which I use everywhere else.
