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From Chamila Wijayarathna <cdwijayarat...@gmail.com>
Subject Re: Understanding what is key and partition key
Date Tue, 16 Dec 2014 13:25:33 GMT
Hi Jack,

So what will be the keys and values of the following CF instance?

year | category | frequency | word1            | word2       | id
------+----------+-----------+------------------+-------------+-------
 2014 |        N |         1 |            සියළුම |         යුද්ධ | 
 664
 2014 |        N |         1 |            එච් |       කාණ්ඩය | 12526
 2014 |        N |         1 |            ගජබා |     සුපර්ක්‍රොස්
| 25779
 2014 |        N |         1 |              බී|       කාණ්ඩය | 12505

Thank You!

On Tue, Dec 16, 2014 at 6:45 PM, Jack Krupansky <jack@basetechnology.com>
wrote:
>
>   Correction: year and category form a “composite partition key”.
>
> frequency, word1, and word2 are “clustering columns”.
>
> The combination of a partition key with clustering columns is a “compound
> primary key”.
>
> Every CQL row will have a partition key by definition, and may optionally
> have clustering columns.
>
> “The key” should just be a synonym for “primary key”, although sometimes
> people are loosely speaking about “the partition” (which should be “the
> partition key”) rather than the CQL “row”.
>
> -- Jack Krupansky
>
>  *From:* Chamila Wijayarathna <cdwijayarathna@gmail.com>
> *Sent:* Tuesday, December 16, 2014 8:03 AM
> *To:* user@cassandra.apache.org
> *Subject:* Understanding what is key and partition key
>
>  Hello all,
>
> I have read a lot about Cassandra and I read about key-value pairs,
> partition keys, clustering keys, etc..
> Is key mentioned in key-value pair and partition key refers to same or are
> they different?
>
>
> CREATE TABLE corpus.bigram_time_category_ordered_frequency (
>     id bigint,
>     word1 varchar,
>     word2 varchar,
>     year int,
>     category varchar,
>     frequency int,
>     PRIMARY KEY((year, category),frequency,word1,word2));
>
>
> In this schema, I know (year, category) is the compound partition key and
> frequency is the clustering key. What is the key here?
>
>
> 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.

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