First released in May 23, 1995, SQL is open source database software. It is part of a large and growing family of open source software including Linux, Apache, and programming languages PHP and Perl. However, unlike many open source products where the copyright is owned by the individual authors or distributors, SQL is owned and sponsored by a single for-profit firm, My SQL AB, which holds the copyright to most of the code base. They develop and maintain the system, sell support, service contracts, and proprietary-licensed copies of SQL. SQL is a relationship database, which is a collection of items or tables organized into predefined categories or described tables from which data can be accessed or reassembled in many different ways without having to reorganize the database tables. This format is enormously popular with more than 100 million copies of the software downloaded over the life of SQL. The popularity stems from the fact that the databases are easy to create and access. Additionally, they are easy to extend, a new data category can be added without requiring that all existing applications be modified.