You need to query against your ItemRatingsByGroup table directly where the group_id equals the group you want. That will give you all the info you want, the item, the group, and the rating.
Michael On 4/15/07, Paul Rauch <[EMAIL PROTECTED]> wrote: > > tejas schrieb: > > Hi - I'm a Django newbie and I have a query that, using the syntax in > > the database API, would become very slow. I'm wondering what the way > > around it is. > > > > I have 3 tables > > > > Group -- contains a list of groups > > > > > > Item: (each item belongs to a group) > > ForeignKey(groupid) > > > > ItemRatingsByGroup: (the rating for each item from each group) > > ForeignKey(groupid) > > ForeignKey(itemid) > > rating > > > > So in the ItemRatingsByGroup Table there at most one row for each > > (item, group) combo (some groups may not have rated an item) > > > > I want to list the items in a group - and also show the rating given > > by that group. Using SQL this would be a left join from Item to > > ItemRatingsByGroup > > > > > > But using the Django ORM (not using exact syntax) > > > > items = Item.objects.get(groupid=desiredgroupid) > > > > for item in items: > > ratings = > > item.item_ratings_by_group_set.filter(groupid=desiredgroupid) > > #there's only 0 or 1 results > > for rating in ratings: > > #display the rating with the item > > > > > > In the Django ORM case, a new query would seem to be executed to get > > the ratings for each item. > > > > Is there anything in Django to help me execute this query (I don't > > think select_related works backwards). Also on a related note, how do > > I find out what queries Django is running? > > > > thanks > > > > > > http://www.djangoproject.com/documentation/faq/#how-can-i-see-the-raw-sql-queries-django-is-running > > here you can see what queries django is running. > > mfg Paul Rauch > > > > -- Michael Trier http://www.railsconsulting.com --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to [EMAIL PROTECTED] 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 -~----------~----~----~----~------~----~------~--~---
