The document discusses Cassandra data modeling using CQL3. It explains that a keyspace contains column families which are similar to SQL tables. Columns are sorted by key and each row's columns are grouped by the row key. The document provides an example of modeling user data with rows containing user id as the key and columns for each attribute like name, email etc. It also shows an example of modeling events data with user id as row key and columns for each event type grouped by timestamp.

1. Making things easy with CQL3
Matt Stump
DataStax

2. id : user1 password : 4cffdce7d84fb56f
email : foobar@example.com
name : Foo

3. id : user1 password : 4cffdce7d84fb56f
email : foobar@example.com
name : Foo
id : user2 password : 4cffdcabef44fb56f
email : bar@example.com
name : Bar

4. id : user1 password : 4cffdce7d84fb56f
email : foobar@example.com
name : Foo
id : user2 password : 4cffdcabef44fb56f
email : bar@example.com
name : Bar
email_marketing : false
permissions : admin

5. id : user1 password : 4cffdce7d84fb56f
email : foobar@example.com
name : Foo
id : user2 password : 4cffdcabef44fb56f
email : bar@example.com
name : Bar
email_marketing : false
permissions : admin
Column Family

6. ColumnFamily
=
SQL Table

7. id : user1 password : 4cffdce7d84fb56f
email : foobar@example.com
name : Foo
id : user2 password : 4cffdcabef44fb56f
email : bar@example.com
name : Bar
email_marketing : false
permissions : admin
Column Family
id : user1 password : 4cffdce7d84fb56f
email : foobar@example.com
name : Foo
id : user2 password : 4cffdcabef44fb56f
email : bar@example.com
name : Bar
email_marketing : false
permissions : admin
Column Family
Keyspace

8. Keyspace
is a collection of
ColumnFamilies

10. id : user2 password : 4cffdcabef44fb56f
email : bar@example.com
name : Bar
email_marketing : false
permissions : admin
Columns are sorted

11. id : user2
password : 4cffdcabef44fb56f
email : bar@example.com
name : Bar
email_marketing : false
permissions : admin
Columns are sorted

14. 2^128

15. 2^128
HASH("user1") = 3

16. 2^128
HASH("user1") = 3

18. id : user1 [event, time] : data
[event, time] : data
[event, time] : data

19. id : user1
[purchase, 2011-02-04] : bread
[event, time] : data
[login, 2011-02-04] : mainpage
[login, 2011-02-03] : mainpage
[purchase, 2011-02-05] : soap

20. id : user1
[purchase, 2011-02-04] : bread
[event, time] : data
[login, 2011-02-04] : mainpage
[login, 2011-02-03] : mainpage
[purchase, 2011-02-05] : soap
id : user2
[purchase, 2013-02-04] : apple
[event, time] : data
[login, 2013-02-03] : twitter

21. References
• http://www.datastax.com/docs
• http://cassandra.apache.org/doc/cql3/CQL.html
• http://www.datastax.com/dev/blog/lightweight-transactions-in-cassandra-2-0