In order to create a database, the PostgreSQL server must be up and running (see Section 18.3).
Databases are created with the SQL command CREATE DATABASE:
CREATE DATABASE name
;
where 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 21.2 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 18.2.) This
database is called
postgres
. So to
create the first “ordinary” database you can connect to
postgres
.
A second database,
template1
,
is 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. More details
appear in Section 22.3.
As a convenience, there is a program you can
execute from the shell to create new databases,
createdb
.
createdb dbname
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 20 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:
CREATE DATABASEdbname
OWNERrolename
;
from the SQL environment, or:
createdb -Orolename
dbname
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).