PostgreSQL is an object relational database management system, which supports a large part of the SQL standard and offers many modern features. It is open-source and is free of cost. Some of the features include complex queries, foreign keys, triggers, updatable views, transactional integrity, and multi-version currency control. PostgreSQL can also be extended by the user in many ways.
For instance, the user can extend it by adding new data types, functions, operators, aggregate functions, index methods and procedural languages. It can run on numerous platforms including Linux, Mac OS X, and Windows. It also supports texts, images, sounds and videos. Besides this, it includes programming interfaces for C/C++, Java, Perl, Python, Ruby, and Open database connectivity (ODBC).