How to install PostgreSQL on CentOS 7

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I. Introduction

PostgreSQL has made its own statement that they are “The World’s Most Advanced Open Source Database”. So what makes PostgreSQL so confident? Then in this article we will learn what Postgresql is and the outstanding features that make Postgresql so powerful around the world in the following article.

What is PostgreSQL?

PostgreSQL is a general-purpose object-relational database management system, the most advanced open source database system available today.

PostgreSQL was developed based on POSTGRES 4.2 at the Berkeley computer science department, University of California. PostgreSQL is designed to run on UNIX-like platforms. However, PostgreSQL was also dynamically adapted to run on many different platforms such as Mac OS X, Solaris, and Windows.

PostgreSQL is a free and open source software. The software’s source code is available under the PostgreSQL license, a freely open source license. Accordingly, you will be free to use, modify, and distribute PostgreSQL in any form.

PostgreSQL does not require too much maintenance because it is highly stable. Therefore, if you develop applications based on PostgreSQL, the cost of ownership will be lower than with other data management systems.

Why use PostgreSQL?

PostgreSQL possesses a diverse set of features to help developers build apps, administrators to protect data integrity, and create a fault-tolerant environment that helps you manage data regardless of location. large or small data sets. Besides the free and open source system, PostgreSQL also has great extensibility.

PostgreSQL follows the SQL standard but does not conflict with traditional features or could lead to harmful architectural decisions. Many SQL standard features are supported, but sometimes slightly different syntax or functions may be available.

Some of the various features of PostgreSQL

1. Data type:

Primitives: Integer, Number, String, Boolean
Structure: Date/Time, Array, Range, UUID
Document: JSON/JSONB, XML, Key-value (Hstore)
Geometry: Point, Line, Circle, Polygon
Customization: Composite, Custom Styles

2. Data integrity:

UNIQUE, NOT NULL
Primary Keys
Foreign Keys
Exclusion constraints
Function Locks/ Explicit Locks, Recommendation Locks/ Advisory Locks

3. Concurrent, performance:

Cataloging: B-tree, Multicolumn, Expressions, Partial
Advanced cataloging: GiST, SP-Gist, KNN Gist, GIN, BRIN, Bloom filters
Complex query planner/optimizer, index-only scan, multi-column statistic.
Transactions, Transactions in the form of nests (through saving points)
Concurrent Version Control (MVCC)
Parallel read query
Table partition
All transaction-independent levels defined in the SQL standard, including Serializable
Reliability, disaster recovery
Write-ahead Logging (WAL)
Replication: Asynchronous, Synchronous, Logical
Point-in-time-recovery (PITR), active standbys
Tablespace
Security: Authentication: GSSAPI, SSPI, LDAP, SCRAM-SHA-256, Certificate and others, Strong Access Control System, Column and Row Level Security
Procedural Languages: PL/PGSQL, Perl, Python (and many more)
External data wrapper: connect to other databases or streams with standard SQL interface
Text Search: Supports international character sets, e.g. via ICU collations , Full text search

II. Installation Instructions

To install PostgreSQL on CentOS 7 you can follow these 4 steps.

Step 1: SSH into your VPS

To install PostgreSQL , we first need to SSH or access your VPS or server as root .

After successful SSH we continue with step 2 to Install PostgreSQL .

Step 2: Install PostgreSQL

At the time of writing this article, the latest version of PostgreSQL is version 13. Before going into the installation, you can check if PostgreSQL Yum RepositoryIs there another new version available and can you install it according to the new version?

Enable PostgreSQL repository

yum -y install https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm

Install PostgreSQL

Once the repository is activated, run the following command to install PostgreSQL:

yum -y install postgresql13 postgresql13-server

Database Initialization

To initialize the PostgreSQL database type run the following command:

/usr/pgsql-13/bin/postgresql-13-setup initdb

Start PostgreSQL

systemctl enable postgresql-13 (Start PostgreSQL with the system) 
systemctl start postgresql-13 (Start PostgreSQL ) 
systemctl status postgresql-13 (Postgresql status )

Step 3: PostgreSQL Roles and Authentication Methods

Database access in PostgreSQL is handled with the concept of Roles. A Role can represent a user or a group of users.

PostgreSQL supports multiple authentication methods. The most commonly used methods are:

Trust – With this method, the Role can connect without a password, as long as the criteria defined in pg_hba.conf are met.
Password – A Role can connect by providing a password. Passwords can be stored as scram-sha-256, md5 or unencrypted text.
Ident – This method is only supported on TCP/IP connections . It works by getting the client OS username, with optional username mapping.
Peer – Similar to Ident but it only supports local connections ( Local ).

PostgreSQL client authentication is defined in a configuration file named pg_hba.conf . By default, for internal connections ( Local ), PostgreSQL will use the Peer authentication method .

The postgres user is automatically created when you install PostgreSQL. This user is the superuser of PostgreSQL and it is equivalent to the root user in MySQL .

To login to the PostgreSQL server as User postgres , you need to first switch to user postgres and then access the PostgreSQL prompt using the psql utility:

sudo su - postgres 
psql

You can also access PostgreSQL without switching users with the sudo command:

sudo -u postgres psql

The postgres user is normally only used with internal connections ( Local ) and a password should not be set for this user.

Step 4: Create Role and PostgreSQL Database

Only superusers and users with CREATEROLE privileges can create new Roles.

In the following example, we will create a new Roles named technology and a database named technology_data and then grant privileges on the database.

Connect to Shell PostgreSQL

sudo -u postgres psql

Create a new PostgreSQL Role

The following command will create a new Role named tech:

create role technology;

Create a new PostgreSQL database

Create a new database named technology_data with the createdb command:

create database technology_data;

Grant permission

To grant permission to user technology on the database technology_data created in the previous step, run the following query:

grant all privileges on database technology_data to technology;

III. Summary

So in this article, We has shown you how to quickly install PostgreSQL on CenOS 7, so that you can experience the most powerful open source database management software available today.