Thanks! On Jan 7, 2:19 am, Daniel Roseman <dan...@roseman.org.uk> wrote: > On Jan 7, 5:07 am, apramanik <abh...@gmail.com> wrote: > > > > > Oops not a join, but still a db hit :). > > > On Jan 6, 9:03 pm, apramanik <abh...@gmail.com> wrote: > > > > Hey all, if I have a foreign key on a model (say Model B has a foreign > > > key to Model A) and I do something like this: > > > > a = A.objects.get( pk = 1 ) > > > b = B.objects.get( pk = 1 ) > > > > if b.a == a : > > > # Do something > > > > Is that inefficient, since its doing a join to pull b.a? Should I be > > > comparing their ids? How do I get that from the b model? Something > > > like this: > > > > if b.a_id == a.id : > > > # Do something > > > > Not sure about the syntax. Thanks! > > If you had done > b = B.objects.select_related().get(pk=1) > that would have done a join, so you would incur some penalty there but > you wouldn't get a separate db hit when you do b.a. > > However, your alternative syntax is correct, and as long as you don't > need to access anything else on b.a it will save you the extra cost. > -- > DR.
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