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.
Re: Understanding what is key and partition key
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 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.
Re: Understanding what is key and partition key
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 j...@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 cdwijayarat...@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.
Re: Understanding what is key and partition key
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.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook Linkedin Twitter On Tue, Dec 16, 2014 at 2:25 PM, Chamila Wijayarathna cdwijayarat...@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 j...@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 cdwijayarat...@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.
Re: Understanding what is key and partition key
Hi Jens, Thank You! On Tue, Dec 16, 2014 at 7:03 PM, Jens Rantil jens.ran...@tink.se wrote: 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.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook Linkedin Twitter On Tue, Dec 16, 2014 at 2:25 PM, Chamila Wijayarathna cdwijayarat...@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 j...@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 cdwijayarat...@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. -- *Chamila Dilshan Wijayarathna,* SMIEEE, SMIESL, Undergraduate, Department of Computer Science and Engineering, University of Moratuwa.
