I'm going to guess that my version is slow since a new query would be run for each row returned by the initial one.
Check out an app called django-debug-toolbar. It has a view that will show you all of the SQL queries generated as a page is built. It will also tell you how long each query took to run. This should allow you to compare the three methods. Brett On 10/28/11 1:44 PM, "Kevin" <kveron...@gmail.com> wrote: >I think the filter I used does work to detect related friends, here is >a Pythonic example of the same code, but done differently without >filters: > >Person.objects.get(name='Person1').friends.get().friends.all() > >Instead of returning back 'Person1', when using filters, this returns >back 'Person0'. > >Person.objects.get(name='Sean').friends.get().friends.get(name='Person0') > >My next question, which would be better optimized for database hits: > >* Brett's example >* using the filter version >* using the Pythonic version, but use select_related(depth=2) option? > >I am trying to make sure the database hits are optimized as this will >be queries multiple times per page hit for different models. Also, >which would be faster to make sure the page loads are not burden when >lots of these types of queries go through? > >Thanks. > >On Oct 28, 1:34 pm, Kevin <kveron...@gmail.com> wrote: >> Thanks. Is this way good for database optimization though? I guess I >> could use select_related(). I was hoping there was a QuerySet I could >> run. >> >> I made this one, although I'm not sure if it works correctly: >> >> >>Person.objects.filter(name='Person1').filter(friends__friends__name='Pers >>on0') >> This outputs "Person1", if I interchange Person0 with Person2, it >> outputs no results. If I use Person1 in both instances, it outputs >> 'Person1'. >> Does this QuerySet return the results I want, or should I use Brett's >> suggestion? >> >> Thanks again. >> >> On Oct 28, 1:21 pm, Brett Epps <brett.e...@quest.com> wrote: >> >> > Try this: >> >> > for friendof0 in Person0.friends.all(): >> > for friendof1 in Person1.friends.all(): >> > if friendof0 == friendof1: >> > # Person 0 and Person 1 share a friend. >> > else: >> > # They have no shared friends. >> >> > Brett >> >> > On 10/28/11 12:59 PM, "Kevin" <kveron...@gmail.com> wrote: >> >> > >Just thought I'd add another example using Python script: >> >> > >Person0 = Person() >> > >Person1 = Person() >> > >Person2 = Person() >> > >Person0.friends.add(Person2) >> > >Person2.friends.add(Person0) >> > >Person2.friends.add(Person1) >> > >Person1.friends.add(Person2) >> >> > >Now, I would like to do the following, but it seems to fail: >> >> > >Person0.friends.all() in Person1.friends.all(). I would like it to >> > >say if Person0 and Person1 share another friend in common. >> >> > >Person0 and Person2 are friends >> > >Person1 and Person2 are friends >> > >Person0 and Person1 are NOT friends, but share a friend in common. >> > >How does one find out that even though Person0 and Person1 are not >> > >friends, they do share Person2 as a friend. >> >> > >I can use my eye on a Python shell to see that Person2 exists on both >> > >Peson0 and Person1, but how does one make the code see it? >> >> > >Sorry for having to clarify this so much, I'm just not sure that my >> > >last post actually explained it properly. >> >> > >Thanks. >> >> > >On Oct 28, 12:30 pm, Kevin <kveron...@gmail.com> wrote: >> > >> Hello, >> >> > >> I am building a model which shares a relation with another model >> > >> using a ManyToManyField. What I need to do, is find out which >>models >> > >> are on both on two seperate ManyToManyField lists. Here is a >>simple >> > >> example of what I am trying to do: >> >> > >> Person: >> > >> friends=ManyToManyField(self) >> >> > >> To find out this persons direct friends, Person.friends... >> > >> To find out which friends this Person shares in common with another >> > >> Person, ???? >> >> > >> Person0: >> > >> Person1 >> > >> Person6 >> > >> Person3 >> > >> Person8 >> >> > >> Person1: >> > >> Person2 >> > >> Person6 >> >> > >> What would be the most optimized QuerySet to find out that both >> > >> Person0 and Person1 are both friends with Person6? >> >> > >> Is there a specific Django app perhaps that can ease develop of >>this >> > >> type of data relations between objects? >> >> > >> Thanks. >> >> > >-- >> > >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 >> > >django-users+unsubscr...@googlegroups.com. >> > >For more options, visit this group at >> > >http://groups.google.com/group/django-users?hl=en. > >-- >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 >django-users+unsubscr...@googlegroups.com. >For more options, visit this group at >http://groups.google.com/group/django-users?hl=en. > -- You received this message because you are subscribed to the Google Groups "Django users" group. 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