Datatypes

Apache Cassandra supports a variety of datatypes. Ruby driver transparently maps each of those datatypes to a specific Ruby type.

Datatypes that map to String can have different encodings.

Cassandra uuid and timeuuid are represented with Cassandra::Uuid and Cassandra::TimeUuid accordingly.

Background

Given

a running cassandra cluster

Using strings

Given

the following schema:

CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3};
USE simplex;
CREATE TABLE mytable (
  a int PRIMARY KEY,
  b ascii,
  c blob,
  d text,
  e varchar,
);
INSERT INTO mytable (a, b, c, d, e)
VALUES (
  0,
  'ascii',
  0x626c6f62,
  'text',
  'varchar'
)

And

the following example:

require 'cassandra'

cluster = Cassandra.cluster
session = cluster.connect("simplex")

row = session.execute("SELECT * FROM mytable").first

puts "Ascii: #{row['b']}"
puts "Blob: #{row['c']}"
puts "Text: #{row['d']}"
puts "Varchar: #{row['e']}"

When

it is executed

Then

its output should contain:

Ascii: ascii
Blob: blob
Text: text
Varchar: varchar

Using numbers

Given

the following schema:

CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3};
USE simplex;
CREATE TABLE mytable (
  a int PRIMARY KEY,
  b bigint,
  c decimal,
  d double,
  e float,
  f int,
  g varint
);
INSERT INTO mytable (a, b, c, d, e, f, g)
VALUES (
  0,
  765438000,
  1313123123.234234234234234234123,
  3.141592653589793,
  3.14,
  4,
  67890656781923123918798273492834712837198237
)

And

the following example:

require 'cassandra'

cluster = Cassandra.cluster
session = cluster.connect("simplex")

row = session.execute("SELECT * FROM mytable").first

puts "Bigint: #{row['b']}"
puts "Decimal: #{row['c']}"
puts "Double: #{row['d']}"
puts "Float: #{row['e']}"
puts "Integer: #{row['f']}"
puts "Varint: #{row['g']}"

When

it is executed

Then

its output should contain:

Bigint: 765438000
Decimal: 0.1313123123234234234234234234123E10
Double: 3.141592653589793
Float: 3.140000104904175
Integer: 4
Varint: 67890656781923123918798273492834712837198237

Using identifiers, booleans and ip addresses

Given

the following schema:

CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3};
USE simplex;
CREATE TABLE mytable (
  a int PRIMARY KEY,
  b boolean,
  c inet,
  d timestamp,
  e timeuuid,
  f uuid
);
INSERT INTO mytable (a, b, c, d, e, f)
VALUES (
  0,
  true,
  '200.199.198.197',
  '2013-12-11 10:09:08+0000',
  FE2B4360-28C6-11E2-81C1-0800200C9A66,
  00b69180-d0e1-11e2-8b8b-0800200c9a66
)

And

the following example:

require 'cassandra'

cluster = Cassandra.cluster
session = cluster.connect("simplex")

row = session.execute("SELECT * FROM mytable").first

puts "Boolean: #{row['b']}"
puts "Inet: #{row['c'].class.name} - #{row['c']}"
puts "Timestamp: #{row['d'].httpdate}"
puts "Timeuuid: #{row['e']}"
puts "Uuid: #{row['f']}"

When

it is executed

Then

its output should contain:

Boolean: true
Inet: IPAddr - 200.199.198.197
Timestamp: Wed, 11 Dec 2013 10:09:08 GMT
Timeuuid: fe2b4360-28c6-11e2-81c1-0800200c9a66
Uuid: 00b69180-d0e1-11e2-8b8b-0800200c9a66

Using lists, maps and sets

Given

the following schema:

CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3};
USE simplex;
CREATE TABLE user (
  id int PRIMARY KEY,
  logins List<timestamp>,
  locations Map<timestamp, double>,
  ip_addresses Set<inet>
);
INSERT INTO user (id, logins, locations, ip_addresses)
VALUES (
  0,
  ['2014-09-11 10:09:08+0000', '2014-09-12 10:09:00+0000'],
  {'2014-09-11 10:09:08+0000': 37.397357},
  {'200.199.198.197', '192.168.1.15'}
)

And

the following example:

require 'cassandra'

cluster = Cassandra.cluster
session = cluster.connect("simplex")

row = session.execute("SELECT * FROM user").first

puts "Logins: #{row['logins'].map(&:httpdate)}"
puts "Location at #{row['locations'].first.first.httpdate}: #{row['locations'].first.last}"
puts "Ip Addresses: #{row['ip_addresses'].inspect}"

When

it is executed

Then

its output should contain:

Logins: ["Thu, 11 Sep 2014 10:09:08 GMT", "Fri, 12 Sep 2014 10:09:00 GMT"]
Location at Thu, 11 Sep 2014 10:09:08 GMT: 37.397357
Ip Addresses: #<Set: {#<IPAddr: IPv4:192.168.1.15/255.255.255.255>, #<IPAddr: IPv4:200.199.198.197/255.255.255.255>}>

Using tuples

Given

the following schema:

CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3};
USE simplex;
CREATE TABLE user (
  id int PRIMARY KEY,
  name frozen <tuple<varchar, varchar>>
);
INSERT INTO user (id, name)
VALUES (0, ('John', 'Smith'))

And

the following example:

require 'cassandra'

cluster = Cassandra.cluster
session = cluster.connect("simplex")

row = session.execute("SELECT * FROM user").first

puts "Name: #{row['name']}"

update = session.prepare("UPDATE user SET name=? WHERE id=0")
session.execute(update, arguments: [Cassandra::Tuple.new('Jane', 'Doe')])

row = session.execute("SELECT * FROM user").first
puts "Name: #{row['name']}"

session.execute("INSERT INTO user (id, name) VALUES (1, (?, ?))", arguments: ['Agent', 'Smith'])
row = session.execute("SELECT * FROM user WHERE id=1").first
puts "Name: #{row['name']}"

insert = session.prepare("INSERT INTO user (id, name) VALUES (?, ?)")
session.execute(insert, arguments: [2, Cassandra::Tuple.new('Apache', 'Cassandra')])
row = session.execute("SELECT * FROM user WHERE id=2").first

puts "Name: #{row['name']}"

begin
  session.execute(update, arguments: [Cassandra::Tuple.new('Jane', 'Doe', 'Extra')])
rescue => e
  puts "#{e.class.name}: #{e.message}"
end

When

it is executed

Then

its output should contain:

Name: (John, Smith)
Name: (Jane, Doe)
Name: (Agent, Smith)
Name: (Apache, Cassandra)
ArgumentError: argument for "name" must be tuple<varchar, varchar>, (Jane, Doe, Extra) given

Using nested collections

Given

the following schema:

  CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3};
  USE simplex;
  CREATE TABLE airports (
    id int PRIMARY KEY,
    flight_destinations Map<int, frozen<Tuple<double, double>>>,
    flight_numbers List<frozen<Set<int>>>
  );
  INSERT INTO airports (id, flight_destinations, flight_numbers)
  VALUES (
    0,
    {747: (37.397357, 42.7357), 458: (122.7423, 2.92547), 638: (105.357423, 20.57925)},
    [{747, 458} , {638}]
  )

And

the following example:

  require 'cassandra'

  cluster = Cassandra.cluster
  session = cluster.connect("simplex")

  row = session.execute("SELECT * FROM airports").first

  puts "Flight_numbers: #{row['flight_numbers'].inspect}"
  row['flight_destinations'].each_pair do | key, value |
    puts "Flight: #{key} to destination: #{value}"
  end

When

it is executed

Then

its output should contain:

Flight_numbers: [#<Set: {458, 747}>, #<Set: {638}>]
Flight: 458 to destination: (122.7423, 2.92547)
Flight: 638 to destination: (105.357423, 20.57925)
Flight: 747 to destination: (37.397357, 42.7357)