幾種常見的NO SQL DB

NO SQL資料庫

Key value型別的
riak
redis
memcached
Oracle Berkeley DB
Hamster DB (embedded database)
Amazon DyamoDB
Project Voldermort(A distributed database)

Document型別的
IBM Cloudant
mongoDB
CouchDB
OrientDB
Couchbase
RAVENDB
terrastore

列儲存型別的
cassandra
HBASE
HYPERTABLE
Amazon SimpleDB
amazon web services

Graph型別的
Neo4j
InfiniteGraph
OrientDB
twitter/flockdb


Document type NO SQL database such as Cloudant DB mainly works for
 - Event logging
 - Blogs and other web applications
 - Operational and meta data for web/mobile applications
Document type NO SQL database were designed with the internet in mind - thinking JSON, RESTFUL API and unstructured data.
ACID is not supported in Cloudant DB, so it is not possible for a document store to handle a transaction that operates over multiple documents

As far as I see, consider NO SQL database when you could not define the database schema or you require a flexible schema for rapid development where your data model may change over time.
Another case is: performance consideration.