Hi Jonathan,
Thank you very much, it worked this way.
On Thu, Nov 13, 2014 at 12:07 AM, Jonathan Haddad <j...@jonhaddad.com> wrote:
> With Cassandra you're going to want to model tables to meet the
> requirements of your queries instead of like a relational database where
> you build tables in 3NF then optimize after.
>
> For your optimized select query, your table (with caveat, see below) could
> start out as:
>
> create table words (
> year int,
> frequency int,
> content text,
> primary key (year, frequency, content) );
>
> You may want to maintain other tables as well for different types of
> select statements.
>
> Your UPDATE statement above won't work, you'll have to DELETE and INSERT,
> since you can't change the value of a clustering column. If you don't know
> what your old frequency is ahead of time (to do the delete), you'll need to
> keep another table mapping content,year -> frequency.
>
> Now, the tricky part here is that the above model will limit the total
> number of partitions you've got to the number of years you're working with,
> and will not scale as the cluster increases in size. Ideally you could
> bucket frequencies. If that feels like too much work (it's starting to for
> me), this may be better suited to something like solr, elastic search, or
> DSE (cassandra + solr).
>
> Does that help?
>
> Jon
>
>
>
>
>
>
> On Wed Nov 12 2014 at 9:01:44 AM Chamila Wijayarathna <
> cdwijayarat...@gmail.com> wrote:
>
>> Hello all,
>>
>> I have a data set with attributes content and year. I want to put them in
>> to CF 'words' with attributes ('content','year','frequency'). The CF should
>> support following operations.
>>
>> - Frequency attribute of a column can be updated (i.e. - : can run
>> query like "UPDATE words SET frequency = 2 WHERE content='abc' AND
>> year=1990;), where clause should contain content and year
>> - Should support select query like "Select content from words where
>> year = 2010 ORDER BY frequency DESC LIMIT 10;" (where clause only has
>> year)
>> where results can be ordered using frequency
>>
>> Is this kind of requirement can be fulfilled using Cassandra? What is the
>> CF structure and indexing I need to use here? What queries should I use to
>> create CF and in indexing?
>>
>>
>> Thank You!
>>
>>
>>
>> --
>> *Chamila Dilshan Wijayarathna,*
>> SMIEEE, SMIESL,
>> Undergraduate,
>> Department of Computer Science and Engineering,
>> University of Moratuwa.
>>
>
--
*Chamila Dilshan Wijayarathna,*
SMIEEE, SMIESL,
Undergraduate,
Department of Computer Science and Engineering,
University of Moratuwa.
