Datahike - A durable datalog database adaptable for distribution.
PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
Datomic - The fully transactional, cloud-ready, distributed database
MySQL - The world's most popular open source database
Matisse - Matisse is a post-relational SQL database.
Oracle DBaaS - See how Oracle Database 12c enables businesses to plug into the cloud and power the real-time enterprise.