PostgreSQL is an object-relational database management system (ORDBMS) based on POSTGRES, Version 4.2. It is an open-source descendant of this original Berkeley code. It supports SQL92 and SQL99 and offers many modern features:
complex queries
foreign keys
triggers
views
transactional integrity
multiversion concurrency control
Also, PostgreSQL can be extended by the user in many ways, for example by adding new
