1. About select_related(): It is said that it will automatically "follow" foreign-key relationships, selecting that additional related-object data when it executes its query. So it is not applicable for ManyToMany relationship, isn't it?
And if select_related() is used, will the queryset method on the related Manager access the DB later? For example: b = Book.objects.select_related().get(id=4) p = b.author # Doesn't hit the database. p.get(pk=3) # Will this action hit the database? 2. About iterator(), 'for' and 'enumerate' on queryset: There is a snippet from the django document page(http:// www.djangoproject.com/documentation/db-api/): iterator() Evaluates the QuerySet (by performing the query) and returns an iterator over the results. ....... Note that using iterator() on a QuerySet which has already been evaluated will force it to evaluate again, repeating the query. And I found the following document of python on iterater and enumarate: iterater http://www.python.org/dev/peps/pep-0234/ This document proposes an iteration interface that objects can provide to control the behaviour of 'for' loops. enumerate() http://www.python.org/dev/peps/pep-0279/ It provides all iterable collections with the same advantage that iteritems() affords to dictionaries -- a compact, readable, reliable index notation. It seems that 'for' loop and enumerate on a QuerySet will use its iterator. Then if I use 'for' loop or enumerate() on a queryset to do some logical task and in the template it will iterate the QuerySet again to display all the data, will the database be hit again? --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
