Hi Puneeth select_related() follows all relationships and pre-caches any foreign key values so that complex trees can be fetched in a single query. However, this isn’t always a good idea, so the depth argument control how many “levels” the select-related behavior will traverse. I could have write the query for you but if you refer this doc link http://www.djangoproject.com/documentation/models/select_related/ and try with yourself then will be good as you are trying to learn Django. Thanks
On Wed, May 6, 2009 at 11:21 AM, Puneet Aggarwal <[email protected]>wrote: > Hello All, > > I am trying to learn django and write a small application. I am facing > issue in executing a join with django. > I am able to find a work around by executing a raw SQL query using cursor. > But that have problem that I need to access fields using > "object.0' or 'object.1' which is too verbose and error prone. > > Is there better way of doing the same thing or executing joins using Django > models. > > here is my table structure > > table 1 : Company > id = IntField > name = CharField > > table 2 : Schmes > id = Int field > Name = CharFiled > comp_id = ForeignKey (company) > > table 3 : Price > > scheme_id = ForeignKey(Schemes) > price = CharField() > Date = DateTimeField() > > I want to execute a query on the price table where I can select the price > of all the schemes for the specified company. > > something like this if I write SQL : > > select price from Price, Schemes, Company where Price.scheme_id = Scheme.id > and Scheme.comp_id = Company.id and Company.id = 1. > > Thanks, > Puneet > > > > _______________________________________________ > BangPypers mailing list > [email protected] > http://mail.python.org/mailman/listinfo/bangpypers > > -- Praveen Kumar +91 9739854134 http://praveensunsetpoint.wordpress.com Bangalore
_______________________________________________ BangPypers mailing list [email protected] http://mail.python.org/mailman/listinfo/bangpypers
