django accessing class variables in a view

Question

hello, i want to make a notification function, and i need fields from 2 different models. how can i access those fields? in my notification view i wrote this

  data = Notices.objects.filter(last_login<date_follow)

where last_login belongs to the model class User , and date_follow to Follow but it is not a proper and correct way of accessing those variables. How can i access them? I need to compare the two dates for realising the notifications that one did not see since his last login.

Thanks!

Answer 1

In general you want to join two tables. In Django this is best possible if you have a foreign key from one table to the other. You maybe want / have your models like this:

class User(models.Model):
  last_login = ...

class Notice(models.Model):
  ...

class Follow(models.Model):
  user = models.ForeignKey(User)
  notice = models.ForeignKey(Notice)
  date_follow = ...

and your query

Notice.objects.filter(follow_set__date_follow__gt = follow_set__user__last_login)

I don't have tested this query, but here 'follow_set' is automatically created by Django and is a Manager which returns the reverse set for the foreign key. If you want, you can use 'related_name' with your foreign key to choose another name here.

Answer 2

Can you show code of your models and query that return error?