PostgreSQLÂ is an object-relational database management system (ORDBMS) based onÂ POSTGRES, Version 4.2, developed at the University of California at Berkeley Computer Science Department. POSTGRES pioneered many concepts that only became available in some commercial database systems much later.
PostgreSQLÂ is an open-source descendant of this original Berkeley code. It supports a large part of the SQL standard and offers many modern features:
- complex queries
- foreign keys
- transactional integrity
- multiversion concurrency control
Also,Â PostgreSQLÂ can be extended by the user in many ways, for example by adding new
- data types
- aggregate functions
- index methods
- procedural languages
And because of the liberal license,Â PostgreSQLÂ can be used, modified, and distributed by anyone free of charge for any purpose, be it private, commercial, or academic.