complex query in django view from different models

I have three models, Which has some common but not exact fields, from a single view ex. home I am retrieving like this

interviews = Interviews.objects.all().order_by('pub_date')[:3]
publications = Publications.objects.all().order_by('pub_date')[:3]
published = Published.objects.all().order_by('pub_date')[:3]

From开发者_如何学C home view I want them to show in template in such order that all the latest/New entries associated with these models will be in top.

like if interview entry 10 is the most recent entry in these all models, then it will be first, then if the published one is second recent it will be second ... etc .etc

Can any one tell me how to do it?

Depending on your other requirements it may be a good idea to make them into sublcasses of a common superclass - containing the common elements.

It's hard to say if it's valid, but if you do you can query the different types of objects separately or together by calling

SuperClass.objects.all().order_by('-pub_date')[:9]

which will render the 9 first objects regerdless of what sublcass they are. Of course assuming the superclass is named SuperClass. Of course this does not insure that there are 3 of each model.

Another simple way of solving it - although admittedly not using a query would simply be to sort the lists.

entries = sorted(list(interviews) + list(publications) + list(published), key=lambda x: x.pub_date, reverse=True)

should work - basically turning them into lists and sorting them.

One possible way is using lambda to sort data, but costs are hiher since you will doing this to python, not DBMS...

lst = []
lst.extend(list(Interviews.objects.order_by('pub_date')[:10]))
lst.extend(list(Publications.objects.order_by('pub_date')[:10]))
lst.extend(list(Published.objects.order_by('pub_date')[:10]))
# take 10 records for each, since you could not know how many records will be picked from which table
# now order them...
lst.sort(lambda x, y: cmp(x.pub_date, y.pub_date))
# and reverse the order, so newset is the first...
lst.reverse()

this will give you a list of objects ordered py pub_date, so you can slice the final list to get any number of records you want...

lst = lst[:10]