In order to create a database, the PostgreSQL server must be up and running (see Section 19.3).
Databases are created with the SQL command CREATE DATABASE:
name follows the usual rules for SQL identifiers. The current role automatically becomes the owner of the new database. It is the privilege of the owner of a database to remove it later (which also removes all the objects in it, even if they have a different owner).
The creation of databases is a restricted operation. See Section 22.2 for how to grant permission.
Since you need to be connected to the database server in order to execute the
CREATE DATABASE command, the question remains how the first database at any given site can be created. The first database is always created by the
initdb command when the data storage area is initialized. (See Section 19.2.) This database is called
postgres. So to create the first “ordinary” database you can connect to
Two additional databases,
template0, are also created during database cluster initialization. Whenever a new database is created within the cluster,
template1 is essentially cloned. This means that any changes you make in
template1 are propagated to all subsequently created databases. Because of this, avoid creating objects in
template1 unless you want them propagated to every newly created database.
template0 is meant as a pristine copy of the original contents of
template1. It can be cloned instead of
template1 when it is important to make a database without any such site-local additions. More details appear in Section 23.3.
createdb does no magic. It connects to the
postgres database and issues the
CREATE DATABASE command, exactly as described above. The createdb reference page contains the invocation details. Note that
createdb without any arguments will create a database with the current user name.
Chapter 21 contains information about how to restrict who can connect to a given database.
Sometimes you want to create a database for someone else, and have them become the owner of the new database, so they can configure and manage it themselves. To achieve that, use one of the following commands:
from the SQL environment, or:
from the shell. Only the superuser is allowed to create a database for someone else (that is, for a role you are not a member of).