Hey, this is a tutorial to keep a note for myself and others. After countless stupid tries, I think I have finally understood the right to install and set up the PostgreSQL database.
1 - Install PostgreSQL
To install the PostgreSQL we need to type the following command.
sudo apt-get update sudo apt-get install postgresql postgresql-contrib
2 - Creating roles and databases
By default, Postgres uses a concept called “roles” to handle authentication and authorization. These are, in some ways, similar to regular Unix-style accounts, but Postgres does not distinguish between users and groups and instead prefers the more flexible term “role”.
Upon installation, Postgres is set up to use ident authentication, meaning that it associates Postgres roles with a matching Unix/Linux system account. If a role exists within Postgres, a Unix/Linux username with the same name is able to sign in as that role.
The installation procedure created a user account called postgres that is associated with the default Postgres role. In order to use Postgres, you can log into that account. There are a few ways to utilize this account to access Postgres.
Switching over to postgres account
sudo -i -u postgres
You can now access the Postgres prompt by typing
3 - Creating a new role
A Postgres Database with a custom user account can be created by the following command in the psql prompt
postgres-# CREATE ROLE your_username WITH LOGIN CREATEDB ENCRYPTED PASSWORD 'your_password';
Above command will create a new role with privileges to login and create databases. Read more
4 - Create a Linux user and access the database
If you don't have a Linux user with role name you specified above then we need to create the user.
For creating the user following command can be used
sudo adduser <role_name> su - <user_name>
Now we need to create the default database which will be used to access the database because the Postgres authentication system makes assumption by default that for any role used to log in, that role will have a database with the same name which it can access.
Hence, we need to create a database without role name. Make sure you're logged in with the Linux user you want to create a database with
Now, we can create any database we want by using the above command and access the psql