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From David Boxenhorn <da...@lookin2.com>
Subject Re: N to N relationships
Date Thu, 09 Dec 2010 17:33:14 GMT
What do you mean by indexing?

On Thu, Dec 9, 2010 at 7:30 PM, Sébastien Druon <sdruon@spotuse.com> wrote:

> Thanks a lot for the answer
>
> What about the indexing when adding a new element? Is it incremental?
>
> Thanks again
>
>
> On 9 December 2010 14:38, David Boxenhorn <david@lookin2.com> wrote:
>
>> How about a regular CF where keys are N@N ?
>>
>> Then, getting a matrix row would be the same cost as getting a matrix
>> column (N gets), and it would be very easy to add element N+1.
>>
>>
>> On Thu, Dec 9, 2010 at 1:48 PM, Sébastien Druon <sdruon@spotuse.com>wrote:
>>
>>> Hello,
>>>
>>> For a specific case, we are thinking about representing a N to N
>>> relationship with a NxN Matrix in Cassandra.
>>> The relations will be only between a subset of elements, so the Matrix
>>> will mostly contain empty elements.
>>>
>>> We have a set of questions concerning this:
>>> - what is the best way to represent this matrix? what would have the best
>>> performance in reading? in writing?
>>>   . a super column family with n column families, with n columns each
>>>   . a column family with n columns and n lines
>>>
>>> In the second case, we would need to extract 2 kinds of information:
>>> - all the relations for a line: this should be no specific problem;
>>> - all the relations for a column: in that case we would need an index for
>>> the columns, right? and then get all the lines where the value of the column
>>> in question is not null... is it the correct way to do?
>>> When using indexes, say we want to add another element N+1. What impact
>>> in terms of time would it have on the indexation job?
>>>
>>> Thanks a lot for the answers,
>>>
>>> Best regards,
>>>
>>> Sébastien Druon
>>>
>>
>>
>

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