doc/src/sgml/ref/grant.sgml

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doc/src/sgml/ref/grant.sgml
PostgreSQL documentation
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<refentry id="sql-grant">
 <indexterm zone="sql-grant">
  <primary>GRANT</primary>
 </indexterm>

 <refmeta>
  <refentrytitle>GRANT</refentrytitle>
  <manvolnum>7</manvolnum>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>GRANT</refname>
  <refpurpose>define access privileges</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
GRANT { { SELECT | INSERT | UPDATE | DELETE | TRUNCATE | REFERENCES | TRIGGER }
    [, ...] | ALL [ PRIVILEGES ] }
    ON { [ TABLE ] <replaceable class="parameter">table_name</replaceable> [, ...]
         | ALL TABLES IN SCHEMA <replaceable class="parameter">schema_name</replaceable> [, ...] }
    TO <replaceable class="parameter">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
    [ GRANTED BY <replaceable class="parameter">role_specification</replaceable> ]

GRANT { { SELECT | INSERT | UPDATE | REFERENCES } ( <replaceable class="parameter">column_name</replaceable> [, ...] )
    [, ...] | ALL [ PRIVILEGES ] ( <replaceable class="parameter">column_name</replaceable> [, ...] ) }
    ON [ TABLE ] <replaceable class="parameter">table_name</replaceable> [, ...]
    TO <replaceable class="parameter">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
    [ GRANTED BY <replaceable class="parameter">role_specification</replaceable> ]

GRANT { { USAGE | SELECT | UPDATE }
    [, ...] | ALL [ PRIVILEGES ] }
    ON { SEQUENCE <replaceable class="parameter">sequence_name</replaceable> [, ...]
         | ALL SEQUENCES IN SCHEMA <replaceable class="parameter">schema_name</replaceable> [, ...] }
    TO <replaceable class="parameter">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
    [ GRANTED BY <replaceable class="parameter">role_specification</replaceable> ]

GRANT { { CREATE | CONNECT | TEMPORARY | TEMP } [, ...] | ALL [ PRIVILEGES ] }
    ON DATABASE <replaceable>database_name</replaceable> [, ...]
    TO <replaceable class="parameter">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
    [ GRANTED BY <replaceable class="parameter">role_specification</replaceable> ]

GRANT { USAGE | ALL [ PRIVILEGES ] }
    ON DOMAIN <replaceable>domain_name</replaceable> [, ...]
    TO <replaceable class="parameter">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
    [ GRANTED BY <replaceable class="parameter">role_specification</replaceable> ]

GRANT { USAGE | ALL [ PRIVILEGES ] }
    ON FOREIGN DATA WRAPPER <replaceable>fdw_name</replaceable> [, ...]
    TO <replaceable class="parameter">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
    [ GRANTED BY <replaceable class="parameter">role_specification</replaceable> ]

GRANT { USAGE | ALL [ PRIVILEGES ] }
    ON FOREIGN SERVER <replaceable>server_name</replaceable> [, ...]
    TO <replaceable class="parameter">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
    [ GRANTED BY <replaceable class="parameter">role_specification</replaceable> ]

GRANT { EXECUTE | ALL [ PRIVILEGES ] }
    ON { { FUNCTION | PROCEDURE | ROUTINE } <replaceable>routine_name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">arg_name</replaceable> ] <replaceable class="parameter">arg_type</replaceable> [, ...] ] ) ] [, ...]
         | ALL { FUNCTIONS | PROCEDURES | ROUTINES } IN SCHEMA <replaceable class="parameter">schema_name</replaceable> [, ...] }
    TO <replaceable class="parameter">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
    [ GRANTED BY <replaceable class="parameter">role_specification</replaceable> ]

GRANT { USAGE | ALL [ PRIVILEGES ] }
    ON LANGUAGE <replaceable>lang_name</replaceable> [, ...]
    TO <replaceable class="parameter">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
    [ GRANTED BY <replaceable class="parameter">role_specification</replaceable> ]

GRANT { { SELECT | UPDATE } [, ...] | ALL [ PRIVILEGES ] }
    ON LARGE OBJECT <replaceable class="parameter">loid</replaceable> [, ...]
    TO <replaceable class="parameter">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
    [ GRANTED BY <replaceable class="parameter">role_specification</replaceable> ]

GRANT { { CREATE | USAGE } [, ...] | ALL [ PRIVILEGES ] }
    ON SCHEMA <replaceable>schema_name</replaceable> [, ...]
    TO <replaceable class="parameter">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
    [ GRANTED BY <replaceable class="parameter">role_specification</replaceable> ]

GRANT { CREATE | ALL [ PRIVILEGES ] }
    ON TABLESPACE <replaceable>tablespace_name</replaceable> [, ...]
    TO <replaceable class="parameter">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
    [ GRANTED BY <replaceable class="parameter">role_specification</replaceable> ]

GRANT { USAGE | ALL [ PRIVILEGES ] }
    ON TYPE <replaceable>type_name</replaceable> [, ...]
    TO <replaceable class="parameter">role_specification</replaceable> [, ...] [ WITH GRANT OPTION ]
    [ GRANTED BY <replaceable class="parameter">role_specification</replaceable> ]

GRANT <replaceable class="parameter">role_name</replaceable> [, ...] TO <replaceable class="parameter">role_specification</replaceable> [, ...]
    [ WITH ADMIN OPTION ]
    [ GRANTED BY <replaceable class="parameter">role_specification</replaceable> ]

<phrase>where <replaceable class="parameter">role_specification</replaceable> can be:</phrase>

    [ GROUP ] <replaceable class="parameter">role_name</replaceable>
  | PUBLIC
  | CURRENT_ROLE
  | CURRENT_USER
  | SESSION_USER
</synopsis>
 </refsynopsisdiv>

 <refsect1 id="sql-grant-description">
  <title>Description</title>

  <para>
   The <command>GRANT</command> command has two basic variants: one
   that grants privileges on a database object (table, column, view, foreign
   table, sequence, database, foreign-data wrapper, foreign server, function, procedure,
   procedural language, schema, or tablespace), and one that grants
   membership in a role.  These variants are similar in many ways, but
   they are different enough to be described separately.
  </para>

 <refsect2 id="sql-grant-description-objects">
  <title>GRANT on Database Objects</title>

  <para>
   This variant of the <command>GRANT</command> command gives specific
   privileges on a database object to
   one or more roles.  These privileges are added
   to those already granted, if any.
  </para>

  <para>
   The key word <literal>PUBLIC</literal> indicates that the
   privileges are to be granted to all roles, including those that might
   be created later.  <literal>PUBLIC</literal> can be thought of as an
   implicitly defined group that always includes all roles.
   Any particular role will have the sum
   of privileges granted directly to it, privileges granted to any role it
   is presently a member of, and privileges granted to
   <literal>PUBLIC</literal>.
  </para>

  <para>
   If <literal>WITH GRANT OPTION</literal> is specified, the recipient
   of the privilege can in turn grant it to others.  Without a grant
   option, the recipient cannot do that.  Grant options cannot be granted
   to <literal>PUBLIC</literal>.
  </para>

  <para>
   If <literal>GRANTED BY</literal> is specified, the specified grantor must
   be the current user.  This clause is currently present in this form only
   for SQL compatibility.
  </para>

  <para>
   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 their own privileges for safety.)
  </para>

  <para>
   The right to drop an object, or to alter its definition in any way, is
   not treated as a grantable privilege; it is inherent in the owner,
   and cannot be granted or revoked.  (However, a similar effect can be
   obtained by granting or revoking membership in the role that owns
   the object; see below.)  The owner implicitly has all grant
   options for the object, too.
  </para>

  <para>
   The possible privileges are:

   <variablelist>
    <varlistentry>
     <term><literal>SELECT</literal></term>
     <term><literal>INSERT</literal></term>
     <term><literal>UPDATE</literal></term>
     <term><literal>DELETE</literal></term>
     <term><literal>TRUNCATE</literal></term>
     <term><literal>REFERENCES</literal></term>
     <term><literal>TRIGGER</literal></term>
     <term><literal>CREATE</literal></term>
     <term><literal>CONNECT</literal></term>
     <term><literal>TEMPORARY</literal></term>
     <term><literal>EXECUTE</literal></term>
     <term><literal>USAGE</literal></term>
     <listitem>
      <para>
       Specific types of privileges, as defined in <xref linkend="ddl-priv"/>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><literal>TEMP</literal></term>
     <listitem>
      <para>
       Alternative spelling for <literal>TEMPORARY</literal>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><literal>ALL PRIVILEGES</literal></term>
     <listitem>
      <para>
       Grant all of the privileges available for the object's type.
       The <literal>PRIVILEGES</literal> key word is optional in
       <productname>PostgreSQL</productname>, though it is required by
       strict SQL.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>

  <para>
   The <literal>FUNCTION</literal> syntax works for plain functions,
   aggregate functions, and window functions, but not for procedures;
   use <literal>PROCEDURE</literal> for those.
   Alternatively, use <literal>ROUTINE</literal> to refer to a function,
   aggregate function, window function, or procedure regardless of its
   precise type.
  </para>

  <para>
   There is also an option to grant privileges on all objects of the same
   type within one or more schemas.  This functionality is currently supported
   only for tables, sequences, functions, and procedures.  <literal>ALL
   TABLES</literal> also affects views and foreign tables, just like the
   specific-object <command>GRANT</command> command.  <literal>ALL
   FUNCTIONS</literal> also affects aggregate and window functions, but not
   procedures, again just like the specific-object <command>GRANT</command>
   command.  Use <literal>ALL ROUTINES</literal> to include procedures.
  </para>
 </refsect2>

 <refsect2 id="sql-grant-description-roles">
  <title>GRANT on Roles</title>

  <para>
   This variant of the <command>GRANT</command> command grants membership
   in a role to one or more other roles.  Membership in a role is significant
   because it conveys the privileges granted to a role to each of its
   members.
  </para>

  <para>
   If <literal>WITH ADMIN OPTION</literal> is specified, the member can
   in turn grant membership in the role to others, and revoke membership
   in the role as well.  Without the admin option, ordinary users cannot
   do that.  A role is not considered to hold <literal>WITH ADMIN
   OPTION</literal> on itself, but it may grant or revoke membership in
   itself from a database session where the session user matches the
   role.  Database superusers can grant or revoke membership in any role
   to anyone.  Roles having <literal>CREATEROLE</literal> privilege can grant
   or revoke membership in any role that is not a superuser.
  </para>

  <para>
   If <literal>GRANTED BY</literal> is specified, the grant is recorded as
   having been done by the specified role.  Only database superusers may
   use this option, except when it names the same role executing the command.
  </para>

  <para>
   Unlike the case with privileges, membership in a role cannot be granted
   to <literal>PUBLIC</literal>.  Note also that this form of the command
   does not allow the noise word <literal>GROUP</literal>
   in <replaceable class="parameter">role_specification</replaceable>.
  </para>
 </refsect2>

 <refsect2 id="sql-grant-description-protocols">
 <title>Grant on Protocols</title>

 <para>
 After creating a custom protocol, specify CREATE TRUSTED PROTOCOL to be able 
 to allowing any user besides the owner to access it. If the protocol is not 
 trusted, you cannot give any other user permission to use it to read or write data. 
 After a TRUSTED protocol is created, you can specify which other users can 
 access it with the GRANT command. 
 </para>

 <para>
  To allow a user to create a readable external table with a trusted protocol
 </para>

 <para> 
  GRANT SELECT ON PROTOCOL protocolname TO username
 </para>

 <para>
  To allow a user to create a writable external table with a trusted protocol
 </para>

 <para>
  GRANT INSERT ON PROTOCOL protocolname TO username
 </para>

 <para>
 To allow a user to create both readable and writable external table with a trusted protocol
 </para>

 <para>
 GRANT ALL ON PROTOCOL protocolname TO username
 </para>

 </refsect2>
 </refsect1>


 <refsect1 id="sql-grant-notes">
  <title>Notes</title>

   <para>
    The <link linkend="sql-revoke"><command>REVOKE</command></link> command is used
    to revoke access privileges.
   </para>

   <para>
    Since <productname>PostgreSQL</productname> 8.1, the concepts of users and
    groups have been unified into a single kind of entity called a role.
    It is therefore no longer necessary to use the keyword <literal>GROUP</literal>
    to identify whether a grantee is a user or a group.  <literal>GROUP</literal>
    is still allowed in the command, but it is a noise word.
   </para>

   <para>
    A user may perform <command>SELECT</command>, <command>INSERT</command>, etc. on a
    column if they hold that privilege for either the specific column or
    its whole table.  Granting the privilege at the table level and then
    revoking it for one column will not do what one might wish: the
    table-level grant is unaffected by a column-level operation.
   </para>

   <para>
    When a non-owner of an object attempts to <command>GRANT</command> privileges
    on the object, the command will fail outright if the user has no
    privileges whatsoever on the object.  As long as some privilege is
    available, the command will proceed, but it will grant only those
    privileges for which the user has grant options.  The <command>GRANT ALL
    PRIVILEGES</command> forms will issue a warning message if no grant options are
    held, while the other forms will issue a warning if grant options for
    any of the privileges specifically named in the command are not held.
    (In principle these statements apply to the object owner as well, but
    since the owner is always treated as holding all grant options, the
    cases can never occur.)
   </para>

   <para>
    It should be noted that database superusers can access
    all objects regardless of object privilege settings.  This
    is comparable to the rights of <literal>root</literal> in a Unix system.
    As with <literal>root</literal>, it's unwise to operate as a superuser
    except when absolutely necessary.
   </para>

   <para>
    If a superuser chooses to issue a <command>GRANT</command> or <command>REVOKE</command>
    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.
    (For role membership, the membership appears to have been granted
    by the containing role itself.)
   </para>

   <para>
    <command>GRANT</command> and <command>REVOKE</command> can also be done by a role
    that is not the owner of the affected object, but is a member of the role
    that owns the object, or is a member of a role that holds privileges
    <literal>WITH GRANT OPTION</literal> on the object.  In this case the
    privileges will be recorded as having been granted by the role that
    actually owns the object or holds the privileges
    <literal>WITH GRANT OPTION</literal>.  For example, if table
    <literal>t1</literal> is owned by role <literal>g1</literal>, of which role
    <literal>u1</literal> is a member, then <literal>u1</literal> can grant privileges
    on <literal>t1</literal> to <literal>u2</literal>, but those privileges will appear
    to have been granted directly by <literal>g1</literal>.  Any other member
    of role <literal>g1</literal> could revoke them later.
   </para>

   <para>
    If the role executing <command>GRANT</command> holds the required privileges
    indirectly via more than one role membership path, it is unspecified
    which containing role will be recorded as having done the grant.  In such
    cases it is best practice to use <command>SET ROLE</command> to become the
    specific role you want to do the <command>GRANT</command> as.
   </para>

   <para>
    Granting permission on a table does not automatically extend
    permissions to any sequences used by the table, including
    sequences tied to <type>SERIAL</type> columns.  Permissions on
    sequences must be set separately.
   </para>

   <para>
    See <xref linkend="ddl-priv"/> for more information about specific
    privilege types, as well as how to inspect objects' privileges.
   </para>
 </refsect1>

 <refsect1 id="sql-grant-examples">
  <title>Examples</title>

  <para>
   Grant insert privilege to all users on table <literal>films</literal>:

<programlisting>
GRANT INSERT ON films TO PUBLIC;
</programlisting>
  </para>

  <para>
   Grant all available privileges to user <literal>manuel</literal> on view
   <literal>kinds</literal>:

<programlisting>
GRANT ALL PRIVILEGES ON kinds TO manuel;
</programlisting>

   Note that while the above will indeed grant all privileges if executed by a
   superuser or the owner of <literal>kinds</literal>, when executed by someone
   else it will only grant those permissions for which the someone else has
   grant options.
  </para>

  <para>
   Grant membership in role <literal>admins</literal> to user <literal>joe</literal>:

<programlisting>
GRANT admins TO joe;
</programlisting></para>
 </refsect1>

 <refsect1 id="sql-grant-compatibility">
  <title>Compatibility</title>

   <para>
    According to the SQL standard, the <literal>PRIVILEGES</literal>
    key word in <literal>ALL PRIVILEGES</literal> is required.  The
    SQL standard does not support setting the privileges on more than
    one object per command.
   </para>

   <para>
    <productname>PostgreSQL</productname> allows an object owner to revoke their
    own ordinary privileges: for example, a table owner can make the table
    read-only to themselves by revoking their own <literal>INSERT</literal>,
    <literal>UPDATE</literal>, <literal>DELETE</literal>, and <literal>TRUNCATE</literal>
    privileges.  This is not possible according to the SQL standard.  The
    reason is that <productname>PostgreSQL</productname> treats the owner's
    privileges as having been granted by the owner to themselves; therefore they
    can revoke them too.  In the SQL standard, the owner's privileges are
    granted by an assumed entity <quote>_SYSTEM</quote>.  Not being
    <quote>_SYSTEM</quote>, the owner cannot revoke these rights.
   </para>

   <para>
    According to the SQL standard, grant options can be granted to
    <literal>PUBLIC</literal>; PostgreSQL only supports granting grant options
    to roles.
   </para>

   <para>
    The SQL standard allows the <literal>GRANTED BY</literal> option to
    specify only <literal>CURRENT_USER</literal> or
    <literal>CURRENT_ROLE</literal>.  The other variants are PostgreSQL
    extensions.
   </para>

   <para>
    The SQL standard provides for a <literal>USAGE</literal> privilege
    on other kinds of objects: character sets, collations,
    translations.
   </para>

   <para>
    In the SQL standard, sequences only have a <literal>USAGE</literal>
    privilege, which controls the use of the <literal>NEXT VALUE FOR</literal>
    expression, which is equivalent to the
    function <function>nextval</function> in PostgreSQL.  The sequence
    privileges <literal>SELECT</literal> and <literal>UPDATE</literal> are
    PostgreSQL extensions.  The application of the
    sequence <literal>USAGE</literal> privilege to
    the <literal>currval</literal> function is also a PostgreSQL extension (as
    is the function itself).
   </para>

   <para>
    Privileges on databases, tablespaces, schemas, and languages are
    <productname>PostgreSQL</productname> extensions.
   </para>
 </refsect1>


 <refsect1>
  <title>See Also</title>

  <simplelist type="inline">
   <member><xref linkend="sql-revoke"/></member>
   <member><xref linkend="sql-alterdefaultprivileges"/></member>
  </simplelist>
 </refsect1>

</refentry>