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GRANT(5)
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 PUBLIC.
There is no need to grant privileges to the owner of an object (usually 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(5)] from any column of the specified table,
view, or sequence. Also allows the use of COPY [copy(5)] TO. For
sequences, this privilege also allows the use of the currval function.
INSERT
Allows INSERT [insert(5)] of a new row into the specified table. Also
allows COPY [copy(5)] FROM.
UPDATE
Allows UPDATE [update(5)] 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(5)] of a row from the specified table.
RULE Allows the creation of a rule on the table/view. (See CREATE RULE
[create_rule(5)] 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(5)] 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 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(5)] 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 privileges to
that view.
Use psql(1)'s \z command to obtain information about existing privileges,
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 column 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
According to the SQL standard, the PRIVILEGES key word in ALL PRIVILEGES is
required. The SQL standard does not support setting the privileges 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(5)]
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