[google-appengine] Re: How to query through multiple models?
> What query would return all parents with children named 'Joe'? De-normalise! Add a StringListProperty to the Parent, and update it with all children of that parent. You can then query the parents directly. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~--~~~~--~~--~--~---
[google-appengine] Re: How to query through multiple models?
I was afraid that would be the answer. On Jan 1, 8:14 pm, Alexander Kojevnikov wrote: > > What query would return all parents with children named 'Joe'? > > De-normalise! Add a StringListProperty to the Parent, and update it > with all children of that parent. You can then query the parents > directly. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~--~~~~--~~--~--~---
[google-appengine] Re: How to query through multiple models?
I´m facing the exactly same problem. I thought about querying all(with a fetch(100), in my case) the children with name 'Joe', and then put all the parent keys in a list(with a list comprehension, maybe). With all the keys, query the Parent using Parent.get(list). Is this acceptable or the de-normalization is the way to go in this case? Thanks --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~--~~~~--~~--~--~---
[google-appengine] Re: How to query through multiple models?
It will certainly work though it's not as efficient as querying de- normalised parents. You can try this approach first and if it's not fast enough for your app, you can always de-normalise later. On Jan 2, 2:59 pm, "Tiago S." wrote: > I´m facing the exactly same problem. I thought about querying all(with > a fetch(100), in my case) the children with name 'Joe', and then put > all the parent keys in a list(with a list comprehension, maybe). With > all the keys, query the Parent using Parent.get(list). > > Is this acceptable or the de-normalization is the way to go in this > case? > > Thanks --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~--~~~~--~~--~--~---
[google-appengine] Re: How to query through multiple models?
Thanks, Alexander! I´ll try that first as I´m still reluctant in doing de-normalization. Regards, On Jan 2, 2:05 am, Alexander Kojevnikov wrote: > It will certainly work though it's not as efficient as querying de- > normalised parents. You can try this approach first and if it's not > fast enough for your app, you can always de-normalise later. > > On Jan 2, 2:59 pm, "Tiago S." wrote: > > > I´m facing the exactly same problem. I thought about querying all(with > > a fetch(100), in my case) the children with name 'Joe', and then put > > all the parent keys in a list(with a list comprehension, maybe). With > > all the keys, query the Parent using Parent.get(list). > > > Is this acceptable or the de-normalization is the way to go in this > > case? > > > Thanks --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~--~~~~--~~--~--~---
[google-appengine] Re: How to query through multiple models?
On Fri, Jan 2, 2009 at 1:59 AM, Tiago S. wrote: > I´m facing the exactly same problem. I thought about querying all(with > a fetch(100), in my case) the children with name 'Joe', and then put > all the parent keys in a list(with a list comprehension, maybe). With > all the keys, query the Parent using Parent.get(list). You can simply do [entity.parent for entity in result]. If you have a ReferenceProperty, the first time you call the property "parent" to get the key, it'll be fetched. So building and fetching a list would only be possible if you store an additional property with the parent key - or you'd be doing double fetch. -- rodrigo --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~--~~~~--~~--~--~---
[google-appengine] Re: How to query through multiple models?
parents = db.get([Entity.parent.get_value_for_datastore(entity) for entity in result]) Is more efficient because you only do 1 call to the datastore, for multiple objects. 2009/1/2 Rodrigo Moraes : > > On Fri, Jan 2, 2009 at 1:59 AM, Tiago S. wrote: >> I´m facing the exactly same problem. I thought about querying all(with >> a fetch(100), in my case) the children with name 'Joe', and then put >> all the parent keys in a list(with a list comprehension, maybe). With >> all the keys, query the Parent using Parent.get(list). > > You can simply do [entity.parent for entity in result]. If you have a > ReferenceProperty, the first time you call the property "parent" to > get the key, it'll be fetched. So building and fetching a list would > only be possible if you store an additional property with the parent > key - or you'd be doing double fetch. > > -- rodrigo > > > > --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~--~~~~--~~--~--~---
[google-appengine] Re: How to query through multiple models?
On Fri, Jan 2, 2009 at 9:25 AM, djidjadji wrote: > parents = db.get([Entity.parent.get_value_for_datastore(entity) for > entity in result]) > > Is more efficient because you only do 1 call to the datastore, for > multiple objects. Awesome... I thought it was not possible to get the key from a ReferenceProperty without fetching the related entity. This is a nice trick. :-) -- rodrigo --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~--~~~~--~~--~--~---
