MySQL is a relational database management system that runs on a wide variety of platforms including MS Windows. There is an estimated install base of over 11 million. Practical operation is the same as other SQL server applications, whereas multi-user sessions can simultaneously access stored data.
Previously owned as a subsidiary of Sun Microsystems, as of April 20th, 2009, Oracle has announced intentions to purchase Sun. Oracle Buys Sun
One of the most popular uses of MySQL is for web applications and is used by many high transaction websites such Facebook. MySQL is fully OBDC compliant as well.
MySQL has consistantly be shown to be very fast performing and highly reliable, both critical to use in a production business environment.
Currently MySQl is available in two license formats: Community Server and Enterprise Subscription.
For the minimal annual fee of $599/server/year Enterprise offers a consistent monthly and quarterly release schedule. Compare to other sql server apps and you will quickly appreciate the value.
Community Server is available for download at no charge and has sporadic updates.