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.
