PostgreSQL, often simply Postgres, is an open source object-relational database management system (ORDBMS) with an emphasis on extensibility and standards compliance. It is released under the PostgreSQL License, a free/open source software license, similar to the MIT License. PostgreSQL is developed by the PostgreSQL Global Development Group, consisting of a handful of volunteers employed and supervised by companies such as Red Hat and EnterpriseDB. It implements the majority of the SQL:2011 standard, is ACID-compliant, is fully transactional (including all DDL statements), has extensible updateable views, data types, operators, index methods, functions, aggregates, procedural languages, and has a large number of extensions written by third parties. PostgreSQL is available for many platforms including Linux, FreeBSD, Solaris, Microsoft Windows and Mac OS X.