PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
Datomic - The fully transactional, cloud-ready, distributed database
SQLite - SQLite Home Page
Google Cloud Datastore - Cloud Datastore is a NoSQL database for your web and mobile applications.
MongoDB - MongoDB (from "humongous") is a scalable, high-performance NoSQL database.
Oracle TimesTen - TimesTen is an in-memory, relational database management system with persistence and...