Cassandra.md

Cassandra

Enter a cqlsh session on a running dockerised Cassandra

docker exec -it cassandra_container_name_or_id cqlsh

Show all keyspaces

describe keyspaces

Use a keyspace

use keyspace_name;

Show all tables

describe tables;

Show schema

describe schema;

Create table with PK(partition_key, clustering_column)

CREATE TABLE table_name(name text, age text, job text, PRIMARY KEY (name, age));

Insert into table

INSERT INTO table_name (name, age, job) VALUES ("Mark", "21", "Developer");

Basic SELECT statement

select * from table_name;

SELECT statement with WHERE and LIMIT

select * from table_name where field_name='field_value' limit 1;

SELECT statement with WHERE on non-PK field (allow filtering)

select * from table_name where non_pk_field_name='field_value' allow filtering;

SELECT with "OR" alternative (in)

select * from keyspace.table_name WHERE field_name in ('something','something_else');

COUNT rows

SELECT COUNT(*) FROM keyspace.table_name;

Return distinct partition keys

SELECT DISTINCT partition_key FROM keyspace.table_name;

Batch insert

BEGIN BATCH
INSERT INTO keyspace.table_name (fieldA, fieldB) VALUES ('hello', 'world');
INSERT INTO keyspace.table_name (fieldA, fieldB) VALUES ('foo', 'bar');
APPLY BATCH;

Batch update

BEGIN BATCH
UPDATE keyspace.table_name SET fieldA='bonjour', fieldB='earth' WHERE fieldC='blah' AND fieldD='something';
UPDATE keyspace.table_name SET fieldA='ola', fieldB='world' WHERE fieldC='halb' AND fieldD='something_else';
APPLY BATCH;

Make output of Cassandra commands a bit prettier

EXPAND ON;