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From Eldad Yamin <elda...@gmail.com>
Subject Re: b-tree
Date Thu, 21 Jul 2011 12:06:39 GMT
Aaron,
Nested set is exactly what I had in mind.
But how will you be able to maintain it while it evolves and new data is
added without transactions?

Thanks!

On Thu, Jul 21, 2011 at 1:44 AM, aaron morton <aaron@thelastpickle.com>wrote:

> Just throwing out a (half baked) idea, perhaps the Nested Set Model of
> trees would work  http://en.wikipedia.org/wiki/Nested_set_model
>
> <http://en.wikipedia.org/wiki/Nested_set_model>* Ever row would represent
> a set with a left and right encoded into the key
> * Members are inserted as columns into *every* set / row they are a member.
> So we are de-normalising and trading space for time.
> * May need to maintain a custom secondary index of the materialised sets.
> e.g. slice a row to get the first column >= the left value you are
> interested in, that is the key for the set.
>
> I've not thought it through much further than that, a lot would depend on
> your data. The top sets may get very big, .
>
> Cheers
>
> -----------------
> Aaron Morton
> Freelance Cassandra Developer
> @aaronmorton
> http://www.thelastpickle.com
>
> On 21 Jul 2011, at 08:33, Jeffrey Kesselman wrote:
>
> Im not sure if I have an answer for you, anyway, but I'm curious....
>
> A b-tree and a binary tree are not the same thing.  A binary tree is a
> basic fundamental data structure,  A b-tree is an approach to storing and
> indexing data on disc for a database.
>
> Which do you mean?
>
> On Wed, Jul 20, 2011 at 4:30 PM, Eldad Yamin <eldad87@gmail.com> wrote:
>
>> Hello,
>> Is there any good way of storing a binary-tree in Cassandra?
>> I wonder if someone already implement something like that and how
>> accomplished that without transaction supports (while the tree keep
>> evolving)?
>>
>> I'm asking that becouse I want to save geospatial-data, and SimpleGeo did
>> it using b-tree:
>> http://www.readwriteweb.com/cloud/2011/02/video-simplegeo-cassandra.php
>>
>> Thanks!
>>
>
>
>
> --
> It's always darkest just before you are eaten by a grue.
>
>
>

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