With the release of MySQL 4.0, the licensing policy of the wildly popular open source database underwent a subtle change. The code libraries that
client programs use to access the native MySQL API, formerly licensed under the LGPL (Lesser General Public License), were converted to the GPL. The
LGPL was designed to exempt "nonfree" programs that link against open source libraries from the GPL's strong requirement to release source code. The
purpose of the LGPL, according to the Free Software Foundation, is "to encourage the widest possible use of a certain library, so that it becomes a
de-facto standard." And indeed, MySQL has become the database pillar of the so-called LAMP platform, whose acronym expands to Linux, Apache, MySQL,
and the trio of Perl, Python, and PHP.
January 20, 2004