CREATE ROLE — define a new database role
CREATE ROLEname
[ [ WITH ]option
[ ... ] ] whereoption
can be: SUPERUSER | NOSUPERUSER | CREATEDB | NOCREATEDB | CREATEROLE | NOCREATEROLE | CREATEUSER | NOCREATEUSER | INHERIT | NOINHERIT | LOGIN | NOLOGIN | CONNECTION LIMITconnlimit
| [ ENCRYPTED | UNENCRYPTED ] PASSWORD 'password
' | VALID UNTIL 'timestamp
' | IN ROLErolename
[, ...] | IN GROUProlename
[, ...] | ROLErolename
[, ...] | ADMINrolename
[, ...] | USERrolename
[, ...] | SYSIDuid
CREATE ROLE
adds a new role to a
PostgreSQL database cluster. A role is
an entity that can own database objects and have database privileges;
a role can be considered a “user”, a “group”, or both
depending on how it is used. Refer to
Chapter 18, Database Roles and Privileges and Chapter 20, Client Authentication for information about managing
users and authentication. You must have CREATEROLE
privilege or be a database superuser to use this command.
Note that roles are defined at the database cluster level, and so are valid in all databases in the cluster.
name
The name of the new role.
SUPERUSER
NOSUPERUSER
These clauses determine whether the new role is a “superuser”,
who can override all access restrictions within the database.
Superuser status is dangerous and should be used only when really
needed. You must yourself be a superuser to create a new superuser.
If not specified,
NOSUPERUSER
is the default.
CREATEDB
NOCREATEDB
These clauses define a role's ability to create databases. If
CREATEDB
is specified, the role being
defined will be allowed to create new databases. Specifying
NOCREATEDB
will deny a role the ability to
create databases. If not specified,
NOCREATEDB
is the default.
CREATEROLE
NOCREATEROLE
These clauses determine whether a role will be permitted to
create new roles (that is, execute CREATE ROLE
).
A role with CREATEROLE
privilege can also alter
and drop other roles.
If not specified,
NOCREATEROLE
is the default.
CREATEUSER
NOCREATEUSER
These clauses are an obsolete, but still accepted, spelling of
SUPERUSER
and NOSUPERUSER
.
Note that they are not equivalent to
CREATEROLE
as one might naively expect!
INHERIT
NOINHERIT
These clauses determine whether a role “inherits” the
privileges of roles it is a member of.
A role with the INHERIT
attribute can automatically
use whatever database privileges have been granted to all roles
it is directly or indirectly a member of.
Without INHERIT
, membership in another role
only grants the ability to SET ROLE
to that other role;
the privileges of the other role are only available after having
done so.
If not specified,
INHERIT
is the default.
LOGIN
NOLOGIN
These clauses determine whether a role is allowed to log in;
that is, whether the role can be given as the initial session
authorization name during client connection. A role having
the LOGIN
attribute can be thought of as a user.
Roles without this attribute are useful for managing database
privileges, but are not users in the usual sense of the word.
If not specified,
NOLOGIN
is the default, except when
CREATE ROLE
is invoked through its alternate spelling
CREATE USER
.
CONNECTION LIMIT
connlimit
If role can log in, this specifies how many concurrent connections the role can make. -1 (the default) means no limit.
PASSWORD
password
Sets the role's password. (A password is only of use for
roles having the LOGIN
attribute, but you
can nonetheless define one for roles without it.) If you do
not plan to use password authentication you can omit this
option. If no password is specified, the password will be set
to null and password authentication will always fail for that
user. A null password can optionally be written explicitly as
PASSWORD NULL
.
ENCRYPTED
UNENCRYPTED
These key words control whether the password is stored
encrypted in the system catalogs. (If neither is specified,
the default behavior is determined by the configuration
parameter password_encryption.) If the
presented password string is already in MD5-encrypted format,
then it is stored encrypted as-is, regardless of whether
ENCRYPTED
or UNENCRYPTED
is specified
(since the system cannot decrypt the specified encrypted
password string). This allows reloading of encrypted
passwords during dump/restore.
Note that older clients may lack support for the MD5 authentication mechanism that is needed to work with passwords that are stored encrypted.
VALID UNTIL
'timestamp
' The VALID UNTIL
clause sets a date and
time after which the role's password is no longer valid. If
this clause is omitted the password will be valid for all time.
IN ROLE
rolename
The IN ROLE
clause lists one or more existing
roles to which the new role will be immediately added as a new
member. (Note that there is no option to add the new role as an
administrator; use a separate GRANT
command to do that.)
IN GROUP
rolename
IN GROUP
is an obsolete spelling of
IN ROLE
.
ROLE
rolename
The ROLE
clause lists one or more existing
roles which are automatically added as members of the new role.
(This in effect makes the new role a “group”.)
ADMIN
rolename
The ADMIN
clause is like ROLE
,
but the named roles are added to the new role WITH ADMIN
OPTION
, giving them the right to grant membership in this role
to others.
USER
rolename
The USER
clause is an obsolete spelling of
the ROLE
clause.
SYSID
uid
The SYSID
clause is ignored, but is accepted
for backwards compatibility.
Use ALTER ROLE to
change the attributes of a role, and DROP ROLE to remove a role. All the attributes
specified by CREATE ROLE
can be modified by later
ALTER ROLE
commands.
The preferred way to add and remove members of roles that are being used as groups is to use GRANT and REVOKE.
The VALID UNTIL
clause defines an expiration time for a
password only, not for the role per se. In
particular, the expiration time is not enforced when logging in using
a non-password-based authentication method.
The INHERIT
attribute governs inheritance of grantable
privileges (that is, access privileges for database objects and role
memberships). It does not apply to the special role attributes set by
CREATE ROLE
and ALTER ROLE
. For example, being
a member of a role with CREATEDB
privilege does not immediately
grant the ability to create databases, even if INHERIT
is set;
it would be necessary to become that role via
SET ROLE before
creating a database.
The INHERIT
attribute is the default for reasons of backwards
compatibility: in prior releases of PostgreSQL,
users always had access to all privileges of groups they were members of.
However, NOINHERIT
provides a closer match to the semantics
specified in the SQL standard.
Be careful with the CREATEROLE
privilege. There is no concept of
inheritance for the privileges of a CREATEROLE
-role. That
means that even if a role does not have a certain privilege but is allowed
to create other roles, it can easily create another role with different
privileges than its own (except for creating roles with superuser
privileges). For example, if the role “user” has the
CREATEROLE
privilege but not the CREATEDB
privilege,
nonetheless it can create a new role with the CREATEDB
privilege. Therefore, regard roles that have the CREATEROLE
privilege as almost-superuser-roles.
PostgreSQL includes a program createuser that has
the same functionality as CREATE ROLE
(in fact,
it calls this command) but can be run from the command shell.
The CONNECTION LIMIT
option is only enforced approximately;
if two new sessions start at about the same time when just one
connection “slot” remains for the role, it is possible that
both will fail. Also, the limit is never enforced for superusers.
Caution must be exercised when specifying an unencrypted password
with this command. The password will be transmitted to the server
in cleartext, and it might also be logged in the client's command
history or the server log. The command createuser, however, transmits
the password encrypted. Also, psql contains a command
\password
that can be used to safely change the
password later.
Create a role that can log in, but don't give it a password:
CREATE ROLE jonathan LOGIN;
Create a role with a password:
CREATE USER davide WITH PASSWORD 'jw8s0F4';
(CREATE USER
is the same as CREATE ROLE
except
that it implies LOGIN
.)
Create a role with a password that is valid until the end of 2004. After one second has ticked in 2005, the password is no longer valid.
CREATE ROLE miriam WITH LOGIN PASSWORD 'jw8s0F4' VALID UNTIL '2005-01-01';
Create a role that can create databases and manage roles:
CREATE ROLE admin WITH CREATEDB CREATEROLE;
The CREATE ROLE
statement is in the SQL standard,
but the standard only requires the syntax
CREATE ROLEname
[ WITH ADMINrolename
]
Multiple initial administrators, and all the other options of
CREATE ROLE
, are
PostgreSQL extensions.
The SQL standard defines the concepts of users and roles, but it regards them as distinct concepts and leaves all commands defining users to be specified by each database implementation. In PostgreSQL we have chosen to unify users and roles into a single kind of entity. Roles therefore have many more optional attributes than they do in the standard.
The behavior specified by the SQL standard is most closely approximated
by giving users the NOINHERIT
attribute, while roles are
given the INHERIT
attribute.