If the Postgres postmaster is up and running we can create some databases to experiment with. Here, we describe the basic commands for managing a database.
Let's say you want to create a database named mydb. You can do this with the following command:
% createdb dbname
    
    Postgres  allows  you to create 
    any number of databases
    at a  given  site  and  you  automatically  become  the
    database  administrator  of  the database you just created.  
    Database names must  have  an  alphabetic  first
    character and are limited to 31 characters in length.
    Not  every  user has authorization to become a database
    administrator.  If Postgres 
    refuses to create databases
    for you, then the site administrator needs to grant you
    permission to  create  databases.   Consult  your  site
    administrator if this occurs.