MySQL is one of the most popular web based database systems. MySQL is an attractive alternative to higher-cost, more complex database technology. It is the world's most popular open source database software.
MySQL is licensed under the GPL, and the important part of the license at this juncture is the reciprocal provision, which essentially ensures that the code currently available must carry with it the rights and privileges currently assigned to its users in perpetuity. MySQL is based on a client/server model, so the black box is the MySQL server and your interface to it is the MySQL client program.
MySQL is the first database used with PHP. MySQL is run by a for-profit corporation (MySQL AB), which owns the code, employs practically all the developers, dictates what direction the software goes in, and has the right to change (indeed, has changed) the licensing terms for use of the software (and documentation). It is a very good database for some things: it is very fast as a read only database, and so is quite good for driving data displays like GBrowse.
MySQL is the world's most popular open source database software, with over 100 million copies of its software downloaded or distributed throughout its history. The company MySQL AB is headquartered in Sweden and Silicon Valley.
MySQL is an important part of the LAMP stack (Linux/Apache/MySQL/Perl-Phyton-PHP), and has grown to be enterprise-ready technology used by large organizations, and Sun is now a major player in the LAMP stack. One of the things that's always been exciting about MySQL is that it is going after a new market of database users with success in the Web 2. What's more, MySQL is virtually the de facto standard relational database for rapid application development, particularly for the Web. Sun's new role as steward of MySQL is sure to ruffle feathers in the software industry, as well — particularly at Oracle, which, with its recent acquisitions, increasingly competes with Sun in the enterprise application platform arena. On the low end, MySQL is an absolute pandemic, and it's already making headway into the mid-tier territory traditionally owned by the likes of Microsoft. The fundamental reason that an estimated half million servers around the world run MySQL is that it provides an incredible amount of database power at a cost that is zero in most cases, and a few hundred dollars in others. But another strong reason is that MySQL is chosen to power web-based database applications is PHP.