I started allocating negative numbers as ids to my entities(these would be part of the key) and it seems to work.
The appengine returns results sorted in the ascending order of keys and hence if I provide keys as -8, -9, -10 etc., I would get the results as -10, -9, -8 and so on which suffices my use case :) On 30 April 2011 22:53, Robert Kluin <robert.kl...@gmail.com> wrote: > Hey Nischal, > You could insert some records with known key names in various > orders and a common value for a property to query on. If the results > come back out key-ordered, that would be a good indication that the > method might work. Also, I *think* there are some videos, groups > posts, and references in the docs (user or code) mentioning entities > in key order. > > > > Robert > > > > > On Sat, Apr 23, 2011 at 23:59, Nischal Shetty <nischalshett...@gmail.com> > wrote: > > @Robert Thank you so much! Any idea how I can confirm on the timestamp + > key > > thingy? I always need it based on timestamp (descending). If that works > then > > it would help me a lot! > > I have looked into exploding indexes. My query would always be equality > > checks over list properties exclusively. I'm hoping that would not be a > > problem? > > Example: > > select from post > > where listproperty := label1 && listproperty := label2 > > sortby time desc > > This is what we currently have. If the timestamp thingy is true then we > > would be able to remove the last line and that would be so damn cool :) > > On 24 April 2011 08:24, Robert Kluin <robert.kl...@gmail.com> wrote: > >> > >> You probably need to be aware of exploding indexes if you're indexing > >> a list property. It is just something you should consider and be > >> aware of. > >> > >> > http://code.google.com/appengine/docs/python/datastore/queries.html#Big_Entities_and_Exploding_Indexes > >> > >> If you're always planning to sort by timestamp, you could consider > >> prepending the timestamp on the Post entity keys. Your entities > >> should then be returned to the app sorted by timestamp without > >> explicitly specifying the sort order. At least that is the case if I > >> recall correctly. > >> > >> > >> Robert > >> > >> > >> > >> > >> On Sat, Apr 23, 2011 at 13:14, nischalshetty <nischalshett...@gmail.com > > > >> wrote: > >> > We're building a new web product. > >> > 1. We have the concept of label in them. > >> > 2. Each post gets one or more label. > >> > 3. The posts have to be displayed sorted according to timestamp in > >> > descending order > >> > We're making use of List<String> (ListProperty) to save these labels > for > >> > each post. It's working well for us. We can now query over multiple > >> > labels > >> > and retrieve posts. > >> > However, we need the posts to be sorted on timestamp in descending > >> > order. > >> > Due to this our query would have the timestamp as the sort order along > >> > with > >> > the label names. Due to this, we need indexes. And the indexes are > being > >> > built for combination of the labels and timestamp. > >> > So, if our query has 2 labels and the sort order then the index would > be > >> > built for these. If we query for 3 labels and sort order we would have > a > >> > new > >> > index and so on. > >> > I wanted to know if there is any other way such that we can avoid the > >> > indexes? Are indexes cool if you anticipate a LOT of data everyday? Is > >> > there > >> > a way to have the posts sorted based on timestamp in a different way? > >> > > >> > > >> > -- > >> > 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. > >> > > >> > >> -- > >> 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. > >> > > > > > > > > > > > > > > > > > > -- > > 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. > > > > -- > 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. > > -- -Nischal twitter: NischalShetty <http://twitter.com/nischalshetty> facebook: Nischal <http://facebook.com/nischal> -- 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.
