CREATE ROLE

Defines a new database role (user or group).

Synopsis

CREATE ROLE <name> [[WITH] <option> [ ... ]]

where option can be:

      SUPERUSER | NOSUPERUSER
    | CREATEDB | NOCREATEDB
    | CREATEROLE | NOCREATEROLE
    | CREATEEXTTABLE | NOCREATEEXTTABLE 
      [ ( <attribute>='<value>'[, ...] ) ]
           where <attributes> and <value> are:
           type='readable'|'writable'
           protocol='gpfdist'|'http'
    | INHERIT | NOINHERIT
    | LOGIN | NOLOGIN
    | REPLICATION | NOREPLICATION
    | BYPASSRLS | NOBYPASSRLS
    | CONNECTION LIMIT <connlimit>
    | [ ENCRYPTED ] PASSWORD '<password>' | PASSWORD NULL
    | VALID UNTIL '<timestamp>' 
    | IN ROLE <role_name> [, ...]
    | IN GROUP <role_name> [, ...]
    | ROLE <role_name> [, ...]
    | ADMIN <role_name> [, ...]
    | USER <role_name> [, ...]
    | SYSID <uid> [, ...]
    | RESOURCE QUEUE <queue_name>
    | RESOURCE GROUP <group_name>
    | [ DENY <deny_point> ]
    | [ DENY BETWEEN <deny_point> AND <deny_point>]

Description

CREATE ROLE adds a new role to a LightDB-A Database system. 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. You must have CREATEROLE privilege or be a database superuser to use this command.

Note that roles are defined at the system-level and are valid for all databases in your LightDB-A Database system.

Parameters

name : The name of the new role.

SUPERUSER NOSUPERUSER : These clauses determine whether the new role is a “superuser”. If SUPERUSER is specified, the role being defined will be 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. 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 (the default) will deny a role the ability to create databases.

CREATEROLE NOCREATEROLE : These clauses determine whether a role will be permitted to create new roles (that is, execute CREATE ROLE). If CREATEROLE is specified, the role being defined will be allowed to create new roles, alter other roles, and drop other roles. NOCREATEROLE (the default) will deny a role the ability to create roles or modify roles other than their own.

CREATEEXTTABLE NOCREATEEXTTABLE : If CREATEEXTTABLE is specified, the role being defined is allowed to create external tables. The default type is readable and the default protocol is gpfdist, if not specified. Valid types are gpfdist, gpfdists, http, and https. NOCREATEEXTTABLE (the default type) denies the role the ability to create external tables. Note that external tables that use the file or execute protocols can only be created by superusers.

: Use the GRANT...ON PROTOCOL command to allow users to create and use external tables with a custom protocol type, including the s3 and pxf protocols included with LightDB-A Database.

INHERIT NOINHERIT : These clauses determine whether a role “inherits” the privileges of roles it is a member of. If specified, INHERIT (the default) allows the role to use whatever database privileges have been granted to all roles it is directly or indirectly a member of. With NOINHERIT, 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.

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. If specified, LOGIN allows a role to log in to a database. A role having the LOGIN attribute can be thought of as a user. Roles with NOLOGIN 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 alternative spelling CREATE USER.

REPLICATION NOREPLICATION : These clauses determine whether a role is a replication role. A role must have this attribute (or be a superuser) in order to be able to connect to the server in replication mode (physical or logical replication) and in order to be able to create or drop replication slots. A role having the REPLICATION attribute is a very highly privileged role, and should only be used on roles actually used for replication. If not specified, NOREPLICATION is the default. You must be a superuser to create a new role having the REPLICATION attribute.

BYPASSRLS NOBYPASSRLS : These clauses determine whether a role bypasses every row-level security (RLS) policy. NOBYPASSRLS is the default. You must be a superuser to create a new role having the BYPASSRLS attribute.

: Note that pg_dump will set row_security to OFF by default, to ensure all contents of a table are dumped out. If the user running pg_dump does not have appropriate permissions, an error will be returned. However, superusers and the owner of the table being dumped always bypass RLS.

CONNECTION LIMIT connlimit : If role can log in, this specifies how many concurrent connections the role can make. The default of -1 means there is no limit. Note that only normal connections are counted towards this limit. Neither prepared transactions nor background worker connections are counted towards this limit.

[ ENCRYPTED ] PASSWORD ‘password’ PASSWORD NULL : 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.

DAY day [ TIME 'time' ]

The two parts of the deny_point parameter use the following formats:

For day:

{'Sunday' | 'Monday' | 'Tuesday' |'Wednesday' | 'Thursday' | 'Friday' | 
'Saturday' | 0-6 }

For time:

{ 00-23 : 00-59 | 01-12 : 00-59 { AM | PM }}

The DENY BETWEEN clause uses two deny_point parameters:

DENY BETWEEN <deny_point> AND <deny_point>

Notes

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 role members of roles is to use GRANT and REVOKE.

The VALID UNTIL clause defines an expiration time for a password only, not for the role per se. The expiration time is not enforced when logging in using a non-password-based authentication method.

The INHERIT attribute governs inheritance of grantable privileges (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 LightDB-A Database, 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 a role has the CREATEROLE privilege but not the CREATEDB privilege, it can create a new role with the CREATEDB privilege. Therefore, regard roles that have the CREATEROLE privilege as almost-superuser-roles.

LightDB-A Database 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.

You must exercise caution when specifying an unencrypted password with this command. The password will be transmitted to the server in clear-text, and it might also be logged in the client’s command history or the server log. The client program createuser, however, transmits the password encrypted. Also, psql contains a command \password that can be used to safely change the password later.

Examples

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 2022:

CREATE USER joelle WITH LOGIN PASSWORD 'jw8s0F4' VALID UNTIL '2023-01-01';

Create a role that can create databases and manage other roles:

CREATE ROLE admin WITH CREATEDB CREATEROLE;

Create a role that does not allow login access on Sundays:

CREATE ROLE user3 DENY DAY 'Sunday';

Create a role that can create readable and writable external tables of type 'gpfdist’:

CREATE ROLE jan WITH CREATEEXTTABLE(type='readable', protocol='gpfdist')
   CREATEEXTTABLE(type='writable', protocol='gpfdist');

Create a role, assigning a resource group:

CREATE ROLE bill RESOURCE GROUP rg_light;

Create a role that belongs to a resource queue:

CREATE ROLE jonathan LOGIN RESOURCE QUEUE poweruser;

Compatibility

CREATE ROLE is in the SQL standard, but the standard only requires the syntax:

CREATE ROLE <name> [WITH ADMIN <rolename>]

Allowing multiple initial administrators, and all the other options of CREATE ROLE, are LightDB-A Database 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 the database implementation. In LightDB-A Database users and roles are unified into a single type of object. 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.