GRANT(l) SQL - Language Statements (2002-11-22) GRANT(l)
NAME
GRANT - define access privileges
SYNOPSIS
GRANT { { SELECT | INSERT | UPDATE | DELETE | RULE | REFERENCES | TRIGGER }
[,...] | ALL [ PRIVILEGES ] }
ON [ TABLE ] tablename [, ...]
TO { username | GROUP groupname | PUBLIC } [, ...]
GRANT { { CREATE | TEMPORARY | TEMP } [,...] | ALL [ PRIVILEGES ] }
ON DATABASE dbname [, ...]
TO { username | GROUP groupname | PUBLIC } [, ...]
GRANT { EXECUTE | ALL [ PRIVILEGES ] }
ON FUNCTION funcname ([type, ...]) [, ...]
TO { username | GROUP groupname | PUBLIC } [, ...]
GRANT { USAGE | ALL [ PRIVILEGES ] }
ON LANGUAGE langname [, ...]
TO { username | GROUP groupname | PUBLIC } [, ...]
GRANT { { CREATE | USAGE } [,...] | ALL [ PRIVILEGES ] }
ON SCHEMA schemaname [, ...]
TO { username | GROUP groupname | PUBLIC } [, ...]
DESCRIPTION
The GRANT command gives specific permissions on an object
(table, view, sequence, database, function, procedural
language, or schema) to one or more users or groups of
users. These permissions 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. Note that 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.
There is no need to grant privileges to the creator of an
object, as the creator has all privileges by default. (The
creator could, however, choose to revoke some of his own
privileges for safety.) Note that the ability to grant and
revoke privileges is inherent in the creator and cannot be
lost. The right to drop an object, or to alter it in any way
not described by a grantable right, is likewise inherent in
the creator, and cannot be granted or revoked.
Depending on the type of object, the initial default
privileges may include granting some privileges to PUBLIC.
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GRANT(l) SQL - Language Statements (2002-11-22) GRANT(l)
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 creator 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(l)] from any column of the
specified table, view, or sequence. Also allows the use
of COPY [copy(l)] TO. For sequences, this privilege
also allows the use of the currval function.
INSERT
Allows INSERT [insert(l)] of a new row into the
specified table. Also allows COPY [copy(l)] FROM.
UPDATE
Allows UPDATE [update(l)] 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(l)] of a row from the specified
table.
RULE Allows the creation of a rule on the table/view. (See
CREATE RULE [create_rule(l)] 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(l)]
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.
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GRANT(l) SQL - Language Statements (2002-11-22) GRANT(l)
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 language 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
specified schema (assuming that the objects' own
privilege requirements 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(l)] 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.
Currently, to grant privileges in PostgreSQL to only a few
columns, you must create a view having the desired columns
and then grant privileges to that view.
Use psql(1)'s \dp command to obtain information about
existing privileges, for example:
lusitania=> \dp mytable
Access privileges for database "lusitania"
Schema | Table | Access privileges
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--------+---------+---------------------------------------
public | mytable | {=r,miriam=arwdRxt,"group todos=arw"}
(1 row)
The entries shown by \dp 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)
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 field 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 example,
{=,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
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SQL92
The PRIVILEGES key word in ALL PRIVILEGES is required. SQL
does not support setting the privileges on more than one
table per command.
The SQL92 syntax for GRANT allows setting privileges for
individual columns within a table, and allows setting a
privilege to grant the same privileges to others:
GRANT privilege [, ...]
ON object [ ( column [, ...] ) ] [, ...]
TO { PUBLIC | username [, ...] } [ WITH GRANT OPTION ]
SQL allows to grant the USAGE privilege on other kinds of
objects: CHARACTER SET, COLLATION, TRANSLATION, DOMAIN.
The TRIGGER privilege was introduced in SQL99. The RULE
privilege is a PostgreSQL extension.
SEE ALSO
REVOKE [revoke(l)]
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