What is PostgreSQL?

PostgreSQL is an object-relational database management system (ORDBMS) based on POSTGRES, Version 4.2, developed at the University of California at Berkeley Computer Science Department. PostgreSQL is open source database system which supports all the below 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

• data types
  
• functions
  
• operators
  
• aggregate functions
  
• index methods
  
• procedural languages
  

License

PostgreSQL can be used, modified, and distributed by anyone free of charge for any purpose, be it private, commercial, or academic