postgresql_setup

-----------------------------------PostgreSQL--------------------------------------------------------
     
              https://linuxhint.com/install-pgadmin4-ubuntu/
     
  !!!!!!!!   Check this first: https://www.pgadmin.org/download/pgadmin-4-python/
     
     
Install PostgreSQL server:
---------------------------

    Install PostgreSQL
sudo apt-get update && sudo apt-get install postgresql



     Check the status of the database with postgresql status command:
/etc/init.d/postgresql status



     After the installation, a postgres user with administration priviliges was created with empty 
     default password. As the first step, we need to set a password for postgres:
sudo -u postgres psql postgres
     psql (12.4)
     Type "help" for help.

     postgres=# \password postgres
     Enter new password: 1234
     Enter it again: 1234
     
     
     
     Create a new database user:
sudo -u postgres createuser --interactive --password user1234
     Shall the new role be a superuser? (y/n) n
     Shall the new role be allowed to create databases? (y/n) y
     Shall the new role be allowed to create more new roles? (y/n) n
     Password: 1234
    

      Edit the pg_hba.conf file (version can be different from 13):
sudo gedit /etc/postgresql/13/main/pg_hba.conf


     In order to be able to run a Spring Boot application with a local PostgreSQL installation, 
     we change the authentication method for the Unix domain socket and local connections to trust.
# "local" is for Unix domain socket connections only
local   all             all                                     trust
# IPv4 local connections:
host    all             all             127.0.0.1/32            trust



    Restart PostgreSQL to enable the changes:
sudo service postgresql restart





Uninstall PostgreSQL server:
-----------------------------
    
    Follow the commands:

sudo apt-get --purge remove postgresql
  
    List all postgres related packages:
dpkg -l | grep postgres

    Remove all the above listed packages using the command :
apt-get --purge remove package1 package2 ...
    
    Confirm all the files and folders related to postgres/postgresql are deleted using the command :
whereis postgres
whereis postgresql 

    Remove all the files and folders listed using rm command.
sudo rm -rf /var/lib/postgresql/
sudo rm -rf /var/log/postgresql/
sudo rm -rf /etc/postgresql/

    Delete the user postgres using the command :
userdel -f postgres