Xeround - Xeround is an elastic, always-on cloud database that lets you run your MySQL applications in the...
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.
Heroku Postgres - Heroku Postgres is an SQL database as a service.
MySQL - The world's most popular open source database
Database Labs - Database Labs offers Postgres as a service.
Clustrix - Clustrix is the leading scale-out SQL database engineered for the cloud.