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From "Jens Rantil" <jens.ran...@tink.se>
Subject Re: Understanding what is key and partition key
Date Tue, 16 Dec 2014 13:33:55 GMT
For the first row, the key is: (2014, N, 1, සියළුම, යුද්ධ) and the value-part
is (664).




Cheers,

Jens


———
Jens Rantil
Backend engineer
Tink AB

Email: jens.rantil@tink.se
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On Tue, Dec 16, 2014 at 2:25 PM, Chamila Wijayarathna
<cdwijayarathna@gmail.com> wrote:

> 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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