PostgreSQL (pronounced ‘post-gres-Q-L’) is a free, open-source object-relational database management system (object-RDBMS), similar to MySQL, and is standards-compliant and extensible. It is commonly used as a back-end for web and mobile applications. PostgreSQL, or ‘Postgres’ as it is nicknamed, adopts the ANSI/ISO SQL standards together, with the revisions.

Pre-Flight Check

These instructions are intended specifically for installing PostgreSQL on CentOS 7.
I’ll be working from a Liquid Web Self Managed CentOS 7 server, and I’ll be logged in as root.

Step 1: Add the PostgreSQL 9.3 Repository

In this case we want to install PostgreSQL 9.3 directly from the Postgres repository. Let’s add that repo:

rpm -iUvh http://yum.postgresql.org/9.3/redhat/rhel-7-x86_64/pgdg-centos93-9.3-1.noarch.rpm

Step 2: Install PostgreSQL

First, you’ll follow a simple best practice: ensuring the list of available packages is up to date before installing anything new.

yum -y update

Then it’s a matter of just running one command for installation via apt-get:

yum -y install postgresql93 postgresql93-server postgresql93-contrib postgresql93-libs --disablerepo=* --enablerepo=pgdg93

PostgreSQL should now be installed.

Step 2: Start PostgreSQL

Configure Postgres to start when the server boots:

systemctl enable postgresql-9.3

Start Postgres:

/usr/pgsql-9.3/bin/postgresql93-setup initdb

systemctl start postgresql-9.3

Step 3: Switch to the Default PostgreSQL User

As part of the installation Postgres adds the system user postgres and is setup to use “ident” authentication. Roles internal to Postgres (which are similar to users) match with a system user account.

Let’s switch into that system user:

su – postgres

And then connect to the PostgreSQL terminal (in the postgres role):

psql

That’s it! You’re connected and ready to run commands in PostgreSQL as the postgres role. In future (Sept 2014) articles we’ll delve into creating new roles, changing a role’s password, creating/deleting databases, backups, etc.