When you create a database object, you become its owner. By
default, only the owner of an object can do anything with the
object. In order to allow other users to use it,
privileges must be granted. (However,
users that have the superuser attribute can always
access any object.)
There are several different privileges: SELECT,
INSERT, UPDATE, DELETE,
RULE, REFERENCES, TRIGGER,
CREATE, TEMPORARY, EXECUTE, and
USAGE. The privileges applicable to a particular
object vary depending on the object's type (table, function, etc).
For complete information on the different types of privileges
supported by PostgreSQL, refer to the
GRANT reference
page. The following sections and chapters will also show you how
those privileges are used.
The right to modify or destroy an object is always the privilege of
the owner only.
Note: To change the owner of a table, index, sequence, or view, use the
ALTER TABLE
command. There are corresponding ALTER commands for
other object types.
To assign privileges, the GRANT command is
used. For example, if joe is an existing user, and
accounts is an existing table, the privilege to
update the table can be granted with
GRANT UPDATE ON accounts TO joe;
To grant a privilege to a group, use this syntax:
GRANT SELECT ON accounts TO GROUP staff;
The special "user" name PUBLIC can
be used to grant a privilege to every user on the system. Writing
ALL in place of a specific privilege grants all
privileges that are relevant for the object type.
To revoke a privilege, use the fittingly named
REVOKE command:
REVOKE ALL ON accounts FROM PUBLIC;
The special privileges of the object owner (i.e., the right to do
DROP, GRANT, REVOKE, etc.)
are always implicit in being the owner,
and cannot be granted or revoked. But the object owner can choose
to revoke his own ordinary privileges, for example to make a
table read-only for himself as well as others.
Ordinarily, only the object's owner (or a superuser) can grant or
revoke privileges on an object. However, it is possible to grant a
privilege "with grant option", which gives the recipient
the right to grant it in turn to others. If the grant option is
subsequently revoked then all who received the privilege from that
recipient (directly or through a chain of grants) will lose the
privilege. For details see the GRANT and REVOKE reference pages.
