You will get better performance if you constrain the initial query, especially if there are many dogs:
rows=db(db.person.id==db.dog.owner,db.dog.kind=='mutt').select() or rows=db(db.person.id==db.dog.owner).select(limitby=100) Since batch get returns the people list in the order that you sent it dog.owners, orderby will be preserved, as long as orderby is on the dogs table: rows=db(db.person.id==db.dog.owner).select(orderby=db.dog.age) I have not tried any of this yet, but I do not see why it would not work. Robin On Feb 1, 1:35 pm, mdipierro <mdipie...@cs.depaul.edu> wrote: > I'll wait for your patch. ;-) > > Massimo > > On Feb 1, 1:22 pm, Robin B <robi...@gmail.com> wrote: > > > To accomplish this: > > rows=db(db.person.id==db.dog.owner).select() > > > In the driver do this: > > do a query: > > dogs=db(db.dogs.id>0).select() > > do a batch get: > > people = db.people([dog.owner for dog in dogs]) > > > merge the 2 lists and return SQLRows. > > > Robin > > > On Feb 1, 1:16 pm, billf <billferr...@blueyonder.co.uk> wrote: > > > > I would like to see how this code looks as well please > > > > On Feb 1, 5:48 pm, Robin B <robi...@gmail.com> wrote: > > > > > This should work for left joins too because batch get returns None > > > > when an id does not exist. > > > > >http://code.google.com/appengine/docs/python/datastore/functions.html > > > > > 1000 results/query, 30 queries/request = 30,000 results/request max > > > > using queries > > > > > I have not seen a limit for results/batch_get so using batch get could > > > > allow ++30,000 results/request > > > > > You have to process everything in under 10 sec else your HTTP request > > > > will time out. > > > > > GAE will be announcing cron very soon, so long running tasks will be > > > > here shortly. > > > > > Robin > > > > > On Feb 1, 11:29 am, mdipierro <mdipie...@cs.depaul.edu> wrote: > > > > > > Can you send me a patch! this would be great! > > > > > > On Feb 1, 10:58 am, Robin B <robi...@gmail.com> wrote: > > > > > > > This is an example from the web2py book: > > > > > > > 1 >>> rows=db(db.person.id==db.dog.owner).select() > > > > > > 2 >>> for row in rows: print row.person.name, 'has', row.dog.name > > > > > > 3 Alex has Skipper > > > > > > 4 Alex has Snoopy > > > > > > 5 Bob has Puppy > > > > > > > This 1 level inner join will be able to be performed on GAE > > > > > > efficiently using batch get, so long as you are joining on a primary > > > > > > key (id). > > > > > > > Joins on GAE! > > > > > > > Robin --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "web2py Web Framework" group. To post to this group, send email to web2py@googlegroups.com To unsubscribe from this group, send email to web2py+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/web2py?hl=en -~----------~----~----~----~------~----~------~--~---
