Here are my notes from the "Not Only SQL: Alternative Data Persistence and Neo4J"-session from Emil Eifrém (@emileifrem) at QCon London 2010. Please note that these are my notes and I might have misinterpreted some parts of the session, hence, read at own risk :-)
4 trends during 2009 that lead up to NOSQL
- #1 data set size: more data will be created during 2010 than all previous years together
- #2 connectedness: blogs, wikis, tagging, ontologies, …
- #3 semi-strucuture
- #4 architecture
The meaning of the term NOSQL is:
- not "Never SQL"
- not "No To SQL"
- is "Not Only SQL"
4 Emerging Categories of NOSQL
- key-value stores (based on Amazon's Dynamo Paper). Example Programmes: Dynomyte, Voldemort
- big table clones (based on Google's Big Table Paper). Example Programmes: HBase, Hypertable, Cassandra (which is used by e.g. Twitter)
- document databases (collection of key-value pairs, inspired by Lotus Notes!). Example Programmes: CouchDB, MongoDB
- graph databases (nodes, relations, key-value pairs). Example Programmes: Sones, Neo4J, AllegroGraph
Grap Database Neo4J
- disk based
- whiteboard friendly: model your datamodel on a whiteboard and the implementation will look about the same!
- scales up
Go check it out here Neo4J. I know I will!