grant
GRANT() SQL Commands GRANT()
NAME
GRANT - define access privileges
SYNOPSIS
GRANT { { SELECT | INSERT | UPDATE | DELETE | RULE | REFERENCES | TRIGGER }
[,...] | ALL [ PRIVILEGES ] }
ON [ TABLE ] tablename [, ...]
TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]
GRANT { { CREATE | TEMPORARY | TEMP } [,...] | ALL [ PRIVILEGES ] }
ON DATABASE dbname [, ...]
TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]
GRANT { EXECUTE | ALL [ PRIVILEGES ] }
ON FUNCTION funcname ([type, ...]) [, ...]
TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]
GRANT { USAGE | ALL [ PRIVILEGES ] }
ON LANGUAGE langname [, ...]
TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]
GRANT { { CREATE | USAGE } [,...] | ALL [ PRIVILEGES ] }
ON SCHEMA schemaname [, ...]
TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]
DESCRIPTION
The GRANT command gives specific privileges on an object (table, view,
sequence, database, function, procedural language, or schema) to one
or more users or groups of users. These privileges are added to those
already granted, if any.
The key word PUBLIC indicates that the privileges are to be granted to
all users, including those that may be created later. PUBLIC may be
thought of as an implicitly defined group that always includes all
users. Any particular user will have the sum of privileges granted
directly to him, privileges granted to any group he is presently a
member of, and privileges granted to PUBLIC.
If WITH GRANT OPTION is specified, the recipient of the privilege may
in turn grant it to others. By default this is not allowed. Grant
options can only be granted to individual users, not to groups or PUB-
LIC.
There is no need to grant privileges to the owner of an object (usu-
ally the user that created it), as the owner has all privileges by
default. (The owner could, however, choose to revoke some of his own
privileges for safety.) The right to drop an object, or to alter its
definition in any way is not described by a grantable privilege; it is
inherent in the owner, and cannot be granted or revoked. It is not
possible for the owner’s grant options to be revoked, either.
Depending on the type of object, the initial default privileges may
include granting some privileges to PUBLIC. The default is no public
access for tables and schemas; TEMP table creation privilege for
databases; EXECUTE privilege for functions; and USAGE privilege for
languages. The object owner may of course revoke these privileges.
(For maximum security, issue the REVOKE in the same transaction that
creates the object; then there is no window in which another user may
use the object.)
The possible privileges are:
SELECT Allows SELECT [select(7)] from any column of the specified ta-
ble, view, or sequence. Also allows the use of COPY [copy(7)]
TO. For sequences, this privilege also allows the use of the
currval function.
INSERT Allows INSERT [insert(7)] of a new row into the specified ta-
ble. Also allows COPY [copy(7)] FROM.
UPDATE Allows UPDATE [update(7)] of any column of the specified table.
SELECT ... FOR UPDATE also requires this privilege (besides the
SELECT privilege). For sequences, this privilege allows the use
of the nextval and setval functions.
DELETE Allows DELETE [delete(7)] of a row from the specified table.
RULE Allows the creation of a rule on the table/view. (See CREATE
RULE [create_rule(7)] statement.)
REFERENCES
To create a foreign key constraint, it is necessary to have
this privilege on both the referencing and referenced tables.
TRIGGER
Allows the creation of a trigger on the specified table. (See
CREATE TRIGGER [create_trigger(7)] statement.)
CREATE For databases, allows new schemas to be created within the
database.
For schemas, allows new objects to be created within the
schema. To rename an existing object, you must own the object
and have this privilege for the containing schema.
TEMPORARY
TEMP Allows temporary tables to be created while using the database.
EXECUTE
Allows the use of the specified function and the use of any
operators that are implemented on top of the function. This is
the only type of privilege that is applicable to functions.
(This syntax works for aggregate functions, as well.)
USAGE For procedural languages, allows the use of the specified lan-
guage for the creation of functions in that language. This is
the only type of privilege that is applicable to procedural
languages.
For schemas, allows access to objects contained in the speci-
fied schema (assuming that the objects’ own privilege require-
ments are also met). Essentially this allows the grantee to
‘‘look up’’ objects within the schema.
ALL PRIVILEGES
Grant all of the privileges applicable to the object at once.
The PRIVILEGES key word is optional in PostgreSQL, though it is
required by strict SQL.
The privileges required by other commands are listed on the reference
page of the respective command.
NOTES
The REVOKE [revoke(7)] command is used to revoke access privileges.
It should be noted that database superusers can access all objects
regardless of object privilege settings. This is comparable to the
rights of root in a Unix system. As with root, it’s unwise to operate
as a superuser except when absolutely necessary.
If a superuser chooses to issue a GRANT or REVOKE command, the command
is performed as though it were issued by the owner of the affected
object. In particular, privileges granted via such a command will
appear to have been granted by the object owner.
Currently, to grant privileges in PostgreSQL to only a few columns,
you must create a view having the desired columns and then grant priv-
ileges to that view.
Use psql(1)’s \z command to obtain information about existing privi-
leges, for example:
=> \z mytable
Access privileges for database "lusitania"
Schema | Table | Access privileges
--------+---------+---------------------------------------
public | mytable | {=r/postgres,miriam=arwdRxt/postgres,"group todos=arw/postgres"}
(1 row)
The entries shown by \z are interpreted thus:
=xxxx -- privileges granted to PUBLIC
uname=xxxx -- privileges granted to a user
group gname=xxxx -- privileges granted to a group
r -- SELECT ("read")
w -- UPDATE ("write")
a -- INSERT ("append")
d -- DELETE
R -- RULE
x -- REFERENCES
t -- TRIGGER
X -- EXECUTE
U -- USAGE
C -- CREATE
T -- TEMPORARY
arwdRxt -- ALL PRIVILEGES (for tables)
* -- grant option for preceding privilege
/yyyy -- user who granted this privilege
The above example display would be seen by user miriam after creating
table mytable and doing
GRANT SELECT ON mytable TO PUBLIC;
GRANT SELECT, UPDATE, INSERT ON mytable TO GROUP todos;
If the ‘‘Access privileges’’ column is empty for a given object, it
means the object has default privileges (that is, its privileges col-
umn is null). Default privileges always include all privileges for the
owner, and may include some privileges for PUBLIC depending on the
object type, as explained above. The first GRANT or REVOKE on an
object will instantiate the default privileges (producing, for exam-
ple, {=,miriam=arwdRxt}) and then modify them per the specified
request.
EXAMPLES
Grant insert privilege to all users on table films:
GRANT INSERT ON films TO PUBLIC;
Grant all privileges to user manuel on view kinds:
GRANT ALL PRIVILEGES ON kinds TO manuel;
COMPATIBILITY
According to the SQL standard, the PRIVILEGES key word in ALL PRIVI-
LEGES is required. The SQL standard does not support setting the priv-
ileges on more than one object per command.
The SQL standard allows setting privileges for individual columns
within a table:
GRANT privileges
ON table [ ( column [, ...] ) ] [, ...]
TO { PUBLIC | username [, ...] } [ WITH GRANT OPTION ]
The SQL standard provides for a USAGE privilege on other kinds of
objects: character sets, collations, translations, domains.
The RULE privilege, and privileges on databases, schemas, languages,
and sequences are PostgreSQL extensions.
SEE ALSO
REVOKE [revoke(7)]
SQL - Language Statements 2008-01-03 GRANT()
