The PostgreSQLExternal Link relational database system is a fast, scalable, and stadards-compliant open source database platform. This guide will help you install and configure PostgreSQL on Fedora 14. We assume you've followed the steps detailed in our getting started guide, and that you're logged into your Linode VPS as root via SSH.
These instructions work with the Linode platform. If you don't have a Linode yet, sign up for a Linux VPS and get started today.
Make sure your /etc/hosts file has proper entries, similar to the ones shown below. Replace “12.34.56.78” with your Linode's public address, “servername” with your short hostname, and “mydomain.com” with your system's domain name.
File: /etc/hosts
127.0.0.1 localhost.localdomain localhost 12.34.56.78 servername.mydomain.com servername
Set your system's hostname by issuing the following commands. Replace “servername” with your system's short hostname.
echo "HOSTNAME=servername" >> /etc/sysconfig/network hostname "servername"
Make sure your system is up to date by issuing the following command:
yum update
Issue the following command to install PostgreSQL and required dependencies:
yum install postgresql postgresql-server
The current version of the database server will be installed, along with several supporting packages. Start the database server with the following commands:
chkconfig postgresql on /etc/init.d/postgresql initdb service postgresql start
Set the Postgresql Password Set a password for the “postgres” user by issuing the following command (be sure to subtitute your postgres password for “CHANGME” below):
passwd postgres su - postgres psql -d template1 -c "ALTER USER postgres WITH PASSWORD 'CHANGEME';"
You should pick a password consisting of numbers, letters, and non-alphanumeric characters. As with other account passwords, it should be a minimum of eight characters in length.
Create a database and connect to it with psql by issuing the following commands:
createdb mytestdb psql mytestdb
You should see output similar to the following:
-bash-4.1$ psql mytestdb psql (8.4.5) Type "help" for help. mytestdb=#
This is the PostgreSQL client shell; you may use it to issue SQL statements. To see a list of available commands, use the following command in the shell:
\h
To get help on a specific command enter it after \h, as shown below for the “SELECT” command:
\h SELECT
To create a table in your test database called “employees”, issue the following command:
CREATE TABLE employees (employee_id int, first_name varchar, last_name varchar);
To insert a record into the table, you would issue a statement like this:
INSERT INTO employees VALUES (1, 'Jack', 'Sprat');
To see the contents of the “employees” table, you would issue a SELECT statement similar to the following:
SELECT * FROM employees;
This would produce output similar to the following:
mytestdb=# SELECT * FROM employees; employee_id | first_name | last_name -------------+------------+----------- 1 | Jack | Sprat (1 row) To exit the psql shell, issue this command: \q
PostgreSQL refers to users as “roles”, which may have different privileges on your databases. If a user is classified as a “superuser” it will have administrative access to the database system. To add a new user to PostgreSQL, issue the following command as the “postgres” user:
createuser alison --pwprompt
You will be asked to specify several values for the new user. To delete this user, issue the following command:
dropuser alison
By default, PostgreSQL uses ident authentication. This means database connections will be granted to local system users that own or have privileges on the database being connected to. Such authentication is useful in cases where a particular system user will be running a program (local scripts, CGI/FastCGI processes owned by separate users, etc). However, you may wish to change this behavior to require passwords. To do so, edit the file /var/lib/pgsql/data/pg_hba.conf as root or the postgres user. Find the following line:
File except: /var/lib/pgsql/data/pg_hba.conf
local all all ident
Change it to the following to use password authentication:
File excerpt: /var/lib/pgsql/data/pg_hba.conf
local all all md5
As root, restart the Postgresql service:
service postgresql restart
Resume these instructions as the postgres user:
su - postgres
To grant all privileges on the table “employees” to a user named “alison”, issue the following commands:
psql mytestdb GRANT ALL ON employees TO alison; \q
To use the database “mytestdb” as “alison”, issue the following command:
psql -U alison -W mytestdb
You will be prompted to enter the password for the “alison” user and given psql shell access to the database.