NoSQL

NoSQL (Non-Relational) Data Stores

For Internet scale SaaS, there is an emerging movement away from relational databases towards Internet scale data stores.   NoSQL stores tend to be non-relational, distributed, horizontally scaleable and eventually consistent rather than provide full ACID guarantees.   There are several flavors of NoSQL databases including key-value (key-tuple) stores, document stores and graph stores.   These stores tend to be delivered as open source or web services and often scale into the petabyte range across hundreds or thousands of machines.

Key-Value, Key-tuple Stores

• Cassandra
• Dynamo
• HBase
• BigTable (Google Service available via App Engine)
• SimpleDB (Amazon service)

Document Stores

• Apache CouchDB
• Apache Jackrabbit

Graph Stores

• neo4j