PostgreSQL is a powerful object-relational database management system, provided under a flexible BSD-style license. PostgreSQL contains many advanced features, is very fast and standards compliant. It supports a large part of the SQL standard and is designed to be extensible by users in many aspects.
Some of the features are: ACID transactions, foreign keys, views, sequences, sub queries, triggers, user-defined types and functions, outer joins, multi version concurrency control. Graphical user interfaces and bindings for many programming languages are available as well.
This is a simple walk-through to install the PostgreSQL database server and the PgAdmin administration application on Ubuntu Linux.
Installing The Database Server
To install PostgreSQL 8.1 you may use the command line and type:
sudo apt-get install postgresql-8.1
GUI for PostgreSQL
To install pgAdmin III, a handy GUI for PostgreSQL, you may use the command line and type:
sudo apt-get install pgadmin3
Basic Server Setup
To start off, we need to change the PostgreSQL postgres user password, we will not be able to access the server otherwise. As the “postgres” Linux user, we will execute the psql command, in a terminal type:
sudo -u postgres psql template1
Then at the new prompt, type these two commands, replacing secret with the new password (up to you ;))
ALTER USER postgres WITH PASSWORD 'secret'; q
To create the first database, which we will call “mydatabase”, simply type :
sudo -u postgres createdb mydatabase
Using pgAdmin III GUI
To get an idea of what PostgreSQL can do, you may start by firing up a graphical client. In a terminal type:
To get a menu entry for pgAdmin do the following…
sudo gedit /usr/share/applications/pgadmin.desktop
[Desktop Entry] Comment= PostgreSQL Administrator III Name=pgAdmin III Encoding=UTF-8 Exec=pgadmin3 Terminal=false Comment[en_GB]=PostgreSQL Administrator III Icon=/usr/share/pixmaps/pgadmin3.xpm Type=Application Categories=GNOME;Application;Database;System; Name[en_GB]=pgAdmin III
Then save the file and exit gedit. You should find the launcher in the System Tools section of the Applications menu.
Managing The Server
Change Authentication Method
We need to edit file pg_hba.conf to change authentification method for accessing PostgreSQL database.
sudo cp /etc/postgresql/pg_hba.conf /etc/postgresql/pg_hba.confbak sudo gedit /etc/postgresql/pg_hba.conf
For example, if you want postgres to manage its own users (not linked with system users), you will add the following line:
# TYPE DATABASE USER IP-ADDRESS IP-MASK METHOD host all all 10.0.0.0 255.255.255.0 password
Which means that on your local network (10.0.0.0/24 – replace with your own local network !), postgres users can connect through the network to the database providing a classical couple user / password.
Create a Database
To create a database with a user that have full rights on the database, use the following command:
sudo -u postgres createuser -D -A -P mynewuser sudo -u postgres createdb -O mynewuser mydatabase
That’s it, now all you have to do is restart the server and all should be working!
sudo /etc/init.d/postgresql-8.1 restart