Updating my Django website's database from a third party service, strategies?
I think you should choose definetely the third alternative, a cron job to update the database regularly seems the best option.
 You don' t need to use a seperate python function, you can schedule a task with celery, which can be easily integrated with django using django-celery
I'm learning Django and to practice I'm currently developing a clone page of YTS, it's a movie torrents repository*. 
As of right now, I scrapped all the movies in the website and have them on a single db table called Movie with all the basic information of each movie (I'm planning on adding one more for Genre).
Every few days YTS will post new movies and I want my clone-web to automatically add them to the database. I'm currently stuck on deciding how to do this:

I was planning on comparing the movie id of the last movie in my db against the last movie in the YTS db each time the user enters the website, but that'd mean make a request to YTS every time my page loads, it'd also mean some very slow code should be executed inside my index() views method.
Another strategy would be to query the last time my db was updated (new entries were introduced) and if it's let's say bigger than a day then request new movies to YTS. Problem with this is I don't seem to find any method to query the time of last db updates. Does it even exist such method?
I could also set a cron job to update the information but I'm having problems to make changes from a separated Python function (I import django.db and such but the interpreter refuses to execute django db instructions).

So, all in all, what's the best strategy to update my database from a third party service/website without bothering the user with loading times? How do you set such updates in non-intrusive way to the user? How do you generally do it?
* I know a torrents website borders the illegal and I'm not intended, in any way, to make my project available to the public