PostgreSQL is an object-relational database management system (ORDBMS). It is an open source system that is known for its close alignment with the SQL standard.

PostgreSQL is one of the world’s most popular database management systems (DBMS), and as of this writing, it is number 5 on the DB-Engines ranking list.

PostgreSQL is developed by the PostgreSQL Global Development Group, which includes various companies and individuals.

PostgreSQL History

PostgreSQL started under the name POSTGRES in 1986 at the University of California at Berkeley. The project was sponsored by the Defense Advanced Research Projects Agency (DARPA), the Army Research Office (ARO), the National Science Foundation (NSF), and ESL, Inc.

After several major releases the POSTGRES project officially ended in 1993 with Version 4.2.

In 1994, Postgres95 was released as an open-source descendant of the original POSTGRES code. One of the changes was that PostQUEL was replaced with SQL.

In 1996, the name Postgres95 was changed to PostgreSQL, starting at version 6.0 in line with the sequence that had started with the original POSTGRES implementation.

PostgreSQL has since become one of the most popular database management systems in the world.

PostgreSQL Features

PostgreSQL comes with many standard and advanced features, including:

  • Fully ACID compliant
  • Complex queries
  • (Compound) primary keys
  • Foreign keys with restricting and cascading updates/deletes,
  • Check constraints, unique constraints, and not null constraints.
  • Joins
  • Views
  • Triggers
  • Stored procedures (in multiple languages -including Java, Perl, Python, Ruby, Tcl, C/C++, and its own PL/pgSQL)
  • Table inheritance
  • A rule system (the query rewrite system).
  • Database events


Users can extend PostgreSQL by adding new:

  • Data types
  • Functions
  • Operators
  • Aggregate functions
  • Index methods
  • Procedural languages


PostgreSQL is highly scalable. It can handle many concurrent users and it can hold a lot of data. Here are some of the limits of PostgreSQL.

Limit Value
Maximum Database Size Unlimited
Maximum Table Size 32 TB
Maximum Row Size 1.6 TB
Maximum Field Size 1 GB
Maximum Rows per Table Unlimited
Maximum Columns per Table 250 – 1600 depending on column types
Maximum Indexes per Table Unlimited


PostgreSQL is a cross platform DBMS and it runs on all major operating systems, including:

  • Linux
  • UNIX
    • AIX
    • BSD
    • HP-UX
    • SGI IRIX
    • Mac OS X
    • Solaris, Tru64
  • Windows

PostgreSQL Admin Tools

There are many administration tools that can be used with PostgreSQL, many of which were built specifically for PostgreSQL.

Some PostgreSQL distributions include administration tools along with the actual PostgreSQL installation.

Here are two:

You can also download the admin tools separately. Here are three of the more popular ones:

  • pgAdmin. Runs on Linux, FreeBSD, Solaris, Mac OSX and Windows. Free.
  • phpPgAdmin. Runs on Windows, Linux, Mac OSX, Unix any web server supporting PHP (any client with a web browser). Free.
  • Aqua Data Studio. Runs on many DBMSs. Runs on Windows, Linux, Mac OSX, Solaris, Java. Costs $499 USD per user.

PostgreSQL Website

You can find out more information about PostgreSQL at the official PostgreSQL website.