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From Colin Vipurs <zodiac...@gmail.com>
Subject Re: Model Question
Date Thu, 25 Mar 2010 08:32:00 GMT
Peter,

Do you think 0-padding the entries would be more efficient than just
implementing your own comparator?

On Wed, Mar 24, 2010 at 10:57 PM, Peter Chang <peter78@gmail.com> wrote:
> If there's not much overhead, I recommend client side as well.
> Otherwise, you can only sort on column. Therefore, you could create some
> sort of inverted index based on the message count.
> User 1 sent 50 messages.
> User 2 sent 10 messages.
> User 3 sent 25 messages.
> Then store a separate index that looks like:
>   ->  50-User-1-Key
>   ->  25-User-2-Key
>   ->  10-User-2-Key
> You'd also have to 0-pad your count so that numbers are correctly compared
> (12 is less than 110) since you'll have to use some lexical-based sorting.
>
>
> On Wed, Mar 24, 2010 at 1:36 PM, Erez Efrati <erezef@gmail.com> wrote:
>>
>> Hi,
>> I can't figure out how to use model the following using column family and
>> the way the columns are sorted (by their name).
>> Lets say I have a list of users and for each user I wish to display a list
>> of all the friends he has ordered by the number of messages they sent him so
>> far (desc from most to least).
>> I can't see how this is going to work since the columns sorting is always
>> by the name of the column and not its value. I thought of having a row for
>> each user and the columns will be the friends that email him. But the column
>> name needs to be the number of messages to be sorted and the value will be
>> the friend's user ID. But then, when a friend is sending a message to
>> another user how do I increment his count of message he sent so far to that
>> user?
>> How can I model this with Cassandra? Is it possible?
>> Thanks in advance,
>> Erez Efrati
>



-- 
Maybe she awoke to see the roommate's boyfriend swinging from the
chandelier wearing a boar's head.

Something which you, I, and everyone else would call "Tuesday", of course.

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