SQL Azure - Microsoft Azure Cloud SQL Database is the developer’s cloud database service. The Azure database as a service is your solution to building and monitoring applications quickly and efficiently.
PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
Database.com - Enterprise cloud database
MySQL - The world's most popular open source database
Heroku Postgres - Heroku Postgres is an SQL database as a service.
Microsoft SQL - Microsoft SQL is a best in class relational database management software that facilitates the database server to provide you a primary function to store and retrieve data.