NoSQLNot Only SQL

Edel Sherratt

What is NoSQL?

• Not Only SQL• Large volumes of data • No schema• Partition tolerance – scale by adding more

commodity servers• Various data models• Various languages• Eventual consistency

Some NoSQL database systems

• Oracle NoSQL Database

• Apache Cassandra• Apache CouchDB• Apache HBase• mongoDB• Google Bigtable

• Redis• Riak• Neo4j• FlockDB• MarkLogic

NoSQL users and applications

• adform, digital advertising• Iovation, fraud prevention• IBM, email client back-end• HP, music streaming• Many, many more

National Library of Wales Welsh newspapers online

• January 2013 Hacathon – http

://hacathonwiki.llgc.org.uk/w/index.php/Main_Page

• Data documentation, mentions couchdb: – http://hacathonwiki.llgc.org.uk/w/index.php/Simple

_introduction_to_the_data– http://

hacathonwiki.llgc.org.uk/w/index.php/ApiDocumentation 

• Current public interface:– http://www.llgc.org.uk/index.php?id=4723

Some advantages of NoSQL

• Scale using clusters of commodity hardware rather than specialist servers

• Handle larger volumes of data and higher transaction rates than rdbms

• Less need for database administrators• Lower startup costs• Lower expansion costs• Few, if any data model restrictions

Some disadvantages• NoSQL immaturity means expert support

scarce• Many data manipulation languages

– reduces portability of queries– reduces transferability of skills

• No schema, reduces database maintainability

• No normalization challenges consistency• Whole document emphasis challenges

analysis of data sets

Summary

• Characteristics of NoSQL• Some NoSQL databases• Advantages and disadvantages