Monday, April 16, 2007

What is postgreSQL?

postgreSQL is an object-relational database management system(ORDBMS) based on postgres.It is an open-source product.It supports a large part of sql standards 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

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

There is a extension called postGIS to the postgreSQL. postGIS supports for geographical objects to the postgreSQL database, allowing it to be backend database for geographic information systems(GIS).


And because of the liberal license, postgreSQL can be used, modified, and distributed by everyone free of charge for any purpose, be it private, commercial, or academic.


How can we install postgresql in debian system.....

Just search in your cache for postgreSQL by typing following in command line


apt-cache search postgresql

then list latest version of the postgresql. For an example, we are going to install postgresql-8.2.To install type following ..

apt-get install postgresql-8.2


During installation it creates a user called postgres. That user can work with postgresql database.

To connect to the database...

First you have to log as postgres user

Initially there are three databases

postgres
template0
template1

To connect postgres database

$ psql postgres


to get help with SQL command
\h

to get help with psql command
\?


Official site for postgreSQL
http://www.postgresql.org/

Online Documentation for postgreSQL
http://www.postgresql.org/doc/

Information about postGIS
postGIS