Getting started with Postgresql

Set up PostgreSQL

PostgreSQL is not like most other software; you can't just install it and use it immediately. You must perform two preliminary steps: PostgreSQL must first be installed and then start.

To set it up, enter:

PostgreSQL-setup –initdb 

This determines where the PostgreSQL databases are located on the computer. 

Now, type the following commands: 

systemctl start postgresql.service
systemctl enable postgresql.service  

The first command launches PostgreSQL for your computer's current session (if you turn it off, PostgreSQL shuts down). On subsequent reboots, PostgreSQL will launch thanks to the second command automatically.

Create a user

You can't use PostgreSQL even though it is running since you haven't been given a user name yet. You must switch to the Postgres special user to accomplish this. While you are still logged in as root, type the following command:

su Postgres 

There is no need to enter a password because you are doing this action as root. The root user is compelling and dangerous since it can act as any user without knowing their password.

Now that you're using Postgres, run two commands to create your user, like the example below (which creates the user cnUser):

createuser cnUser
createdb cnUser 

Set up a database

On the command line, type psql to launch PostgreSQL. To indicate that you are using PostgreSQL and can only use commands that it understands, you should see something like cnUser=> to the left of each line. You already have a database that contains nothing. In the context of PostgreSQL, a database is only a workspace. You build tables in that area. The data that makes up your database is listed underneath each variable in a table that has a list of variables. 

CREATE TABLE demoTable (
    date date,
    name varchar(60),
    place varchar(60),
    cost numeric(6,2)
); 

Exit PostgreSQL

Finally, enter the following in the terminal to exit PostgreSQL: 

quit  

Or you can type

\q 

Frequently asked questions

What is the precondition for creating a database in PostgreSQL?

To create a database in PostgreSQL, the user must be a superuser or have the appropriate privileges to create a database.

What are the ways of creating a database in PostgreSQL?

There are two ways of creating a database in PostgreSQL. These are:

1. Using CREATE DATABASE command on PostgreSQL shell prompt.
2. Using createdb command on command prompt.

What is the default template in which the new database is created?

The default template in which the new database is created is template1. It is an empty database that contains some default database objects.

How can we see our databases in PostgreSQL?

We can see our databases in PostgreSQL using the \l (backslash l) command. \l or \list is a psql tool that lists all the databases present in the current server. 

Conclusion

In this blog, we have extensively discussed getting started with PostgreSQL and have seen the installation process in detail for Windows, Linux, and macOS.We also learned how to use the PostgreSQL database in brief. I hope you like the content.

If you want to explore more about PostgreSQL and about other databases then refer to these links, MongoDB, Databases, and relational databases, non-relational databases. Also, look at the Coding Ninjas website for some great information, Web Development, Coding Ninjas Studio Problems, Coding Ninjas Studio Interview Bundle, Coding Ninjas Studio Interview Experiences, Coding Ninjas Courses, Coding Ninjas Studio Contests, and Coding Ninjas Studio Test Series. 

Do upvote our blog to help other ninjas grow.

Happy Coding!