PostgreSQL is an object-relational database management system (ORDBMS). It is released under a BSD-style license and is thus free software. As with many other open-source programs, PostgreSQL is not controlled by any single company, but relies on a global community of developers and companies to develop it.
Product name
The mixed-capitalization of the PostgreSQL name can confuse some people on first viewing. The several pronunciations of 'SQL' can lead to this confusion. PostgreSQL's developers pronounce it /poːst ɡɹɛs kjuː ɛl/; (Audio sample, 5.6k MP3). It is also common to hear it abbreviated as simply "postgres", which was its original name. Because of ubiquitous support for the SQL Standard amongst most relational databases, the community considered changing the name back to Postgres. However, the PostgreSQL Core Team announced in 2007 that the product would continue to be named PostgreSQL. The name refers to the project's origins as a "post-Ingres" database, the original authors having also developed the Ingres database.
History
PostgreSQL evolved from the Ingres project at University of California, Berkeley. In 1982, the project leader, Michael Stonebraker, left Berkeley to commercialize Ingres. He returned to Berkeley in 1985 and started a post-Ingres project to address the problems with contemporary database systems that had become increasingly clear during the early 1980s. The new project, Postgres, aimed to add the fewest features needed to completely support types. These features included the ability to define types and to fully describe relationships – something used widely before but maintained entirely by the user. In Postgres, the database "understood" relationships, and could retrieve information in related tables in a natural way using rules. Postgres used many ideas of Ingres but not its code.
Starting in 1986, the team published a number of papers describing the basis of the system, and by 1988 had a prototype version. The team released version 1 to a small number of users in June 1989, then version 2 with a re-written rules system in June 1990. Version 3, released in 1991, again re-wrote the rules system, and added support for multiple storage managers and an improved query engine. By 1993 the great number of users began to overwhelm the project with requests for support and features. After releasing version 4 — primarily a cleanup — the project ended.
But open-source developers could obtain copies and develop the system further, because Berkeley had released Postgres under the BSD license. In 1994, Berkeley graduate students Andrew Yu and Jolly Chen replaced the Ingres-based QUEL query language interpreter with one for the SQL query language, creating Postgres95. The code was released on the web.
In July 1996, Marc Fournier at Hub.Org Networking Services provided the first non-university development server for the open source development effort. Along with Bruce Momjian and Vadim B. Mikheev, work began to stabilize the code inherited from Berkeley. The first open source version was released on August 1, 1996.
In 1996, the project was renamed to PostgreSQL to reflect its support for SQL. The first PostgreSQL release formed version 6.0 in January 1997. Since then, the software was maintained by a group of database developers and volunteers around the world, coordinating via the Internet.
Although the license allowed for the commercialization of Postgres, the code did not develop commercially at first — somewhat surprisingly considering the advantages Postgres offered. The main offshoot originated when Paula Hawthorn (an original Ingres team member who moved from Ingres) and Michael Stonebraker formed Illustra Information Technologies to commercialize Postgres.
In 2000, former Red Hat investors created the company Great Bridge to commercialize PostgreSQL and compete against commercial database vendors. Great Bridge sponsored several PostgreSQL developers and donated many resources back to the community, but by late 2001 closed due to tough competition from companies like Red Hat and to poor market conditions.
In 2001, Command Prompt, Inc. released Mammoth PostgreSQL, the oldest surviving commercial PostgreSQL distribution. It continues to actively support the PostgreSQL community through developer sponsorships and projects including PL/Perl, PL/php, and hosting of community projects such as the PostgreSQL Build Farm.
In January 2005, PostgreSQL received backing by database vendor Pervasive Software, known for its Btrieve product which was ubiquitous on the Novell NetWare platform. Pervasive announced commercial support and community participation and achieved some success. But in July 2006, it left the PostgreSQL support market.
In mid-2005 two other companies announced plans to commercialize PostgreSQL with focus on separate niche markets. EnterpriseDB added functionality to allow applications written to work with Oracle to be more readily run with PostgreSQL. Greenplum contributed enhancements directed at data warehouse and business intelligence applications, including the BizGres project.
In October 2005, John Loiacono, executive vice president of software at Sun Microsystems, commented: "We're not going to OEM Microsoft but we are looking at PostgreSQL right now," although no specifics were released at that time. By November 2005, Sun had announced support for PostgreSQL. By June 2006, Sun Solaris 10 (6/06 release) shipped with PostgreSQL.
In August 2007, EnterpriseDB announced the Postgres Resource Center and EnterpriseDB Postgres, designed to be a fully configured distribution of PostgreSQL including many contrib modules and add-on components. EnterpriseDB Postgres was renamed to Postgres Plus in March 2008.
The PostgreSQL project continues to make yearly major releases and minor "bugfix" releases, all available under the BSD license, based on contributions from both commercial vendors, support companies, and open source programmers at large.
(From http://en.wikipedia.org/wiki/Postgres on November 25, 2008)
PostgreSQL is released under the BSD license.
PostgreSQL Database Management System
(formerly known as Postgres, then as Postgres95)
Portions Copyright (c) 1996-2009, The PostgreSQL Global Development Group
Portions Copyright (c) 1994, The Regents of the University of California
Permission to use, copy, modify, and distribute this software and its documentation for any purpose, without fee, and without a written agreement is hereby granted, provided that the above copyright notice and this paragraph and the following two paragraphs appear in all copies.
IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
Different people involved in PostgreSQL
The founders of Postgres
Michael Stonebraker is a computer scientist specializing in database research and development. His career covers, and helped create, the majority of the existing relational database market today. He is also the founder of Ingres, Illustra, Cohera, StreamBase Systems and Vertica and was previously the CTO of Informix. He is also an editor for the book Readings in Database Systems.
Stonebraker earned his bachelor's degree from Princeton University in 1965 and his master's degree and his Ph.D. from the University of Michigan in 1967 and 1971, respectively. He has received several awards, including the IEEE John von Neumann Medal and the very first SIGMOD Edgar F. Codd Innovations Award. In 1994 he was inducted as a Fellow of the Association for Computing Machinery.
Michael Stonebraker was a Professor of Computer Science at University of California, Berkeley for twenty five years where he developed the INGRES and POSTGRES relational database systems. He is currently an adjunct professor at MIT.
Ingres
In 1973 Stonebraker and his colleague Eugene Wong decided to start researching relational database systems after reading a series of seminal papers published by IBM. By the mid-1970s they had produced, using a rotating team of student programmers, a usable system known as Ingres. At the time Ingres was considered "low end" compared to IBM's similar effort, System R, as it ran on Unix-based DEC machines as opposed to the "big iron" IBM mainframes.
However by the early 1980s the performance and capabilities of these low-end machines was seriously threatening IBM's mainframe market, and with it came the ability of Ingres to be a "real" product for a large number of applications. Ingres was offered using a variation of the BSD license for a nominal fee, and soon a number of companies took advantage of this to create commercial versions of Ingres.
This included Stonebraker, who helped found Relational Technology, Inc., later called Ingres Corporation. Later sold to Computer Associates, Ingres was re-established as an independent company in 2005.
Postgres
Upon his return he started a "post-ingres" effort to address the limitations of the relational model, naming the new project Postgres. Postgres offered a number of features that effectively made the database "understand" the data inside it, dramatically improving programmability. Postgres was also offered using a BSD-like license, and the code forms the basis of today's free software, PostgreSQL.
Stonebraker helped commercialize the code, creating Illustra.
Cohera
In the late 1990s, Mike Stonebraker founded Cohera Software, headquartered in Hayward, California. Cohera's initial mission was to build a federated database, an updated approach to integrating data in multiple databases that began with the first attempts at distributed relational databases in the 1980s. The federated database market had not seen significant customer demand by the 1999-2000 time frame, so Cohera was re-focused on delivering industry-specific capabilities on top of the core integration engine. Cohera was ultimately sold in August 2001 to PeopleSoft.
StreamBase
Mike Stonebraker moved to MIT in the late 1990's and set up a project called Aurora (http://www.cs.brown.edu/research/aurora/). Aurora is about data management for streaming data, using a SQL variant called StreamSQL. StreamBase Systems (http://www.streambase.com) is the company he founded to commercialize the technology.
Vertica and C-Store
Another project Stonebraker has been involved in is C-Store, a column-oriented DBMS. The technology is being commercialized by Vertica Systems, which he co-founded and is serving as Chief Technical Officer.
Additional work
On his second return to academia, he initiated the Mariposa project which became the basis of Cohera which was subsequently sold to PeopleSoft.
(From http://en.wikipedia.org/wiki/Michael_Stonebraker on November 25, 2008)