PostgreSQL (http://www.postgresql.org/) has many rich features. It provides enterprise level services including performance, unique features, and scalability. It has a very supportive community and very good documentation.
The name PostgreSQL is derived from post-ingres database. PostgreSQL history could be summarized as follows:
Academia: University of California at Berkeley (UCB)
1977-1985, the Ingres project: Michael Stonebraker created an RDBMS based on the formal relational model.
1986-1994, postgres: Michael Stonebraker created postgres in order to support complex data types and the object relational model.
1995, Postgres95: Andrew Yu and Jolly Chen changed the postgres POSTQUEL query language with an extended subset of SQL
Industry
1996, PostgreSQL: Several developers dedicated a lot of labor and time to stabilize postgres95. The first open source version was released on January 29, 1997. With the introduction of new features, enhancements...