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<title>5.6.Privileges</title>
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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="ddl-priv"></a>5.6.Privileges</h2></div></div></div>
<a name="id576540"></a><a name="id576552"></a><p> 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,
<em class="firstterm">privileges</em> must be granted. (However,
users that have the superuser attribute can always
access any object.)
</p>
<p> There are several different privileges: <code class="literal">SELECT</code>,
<code class="literal">INSERT</code>, <code class="literal">UPDATE</code>, <code class="literal">DELETE</code>,
<code class="literal">RULE</code>, <code class="literal">REFERENCES</code>, <code class="literal">TRIGGER</code>,
<code class="literal">CREATE</code>, <code class="literal">TEMPORARY</code>, <code class="literal">EXECUTE</code>, and
<code class="literal">USAGE</code>. 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 <span class="productname">PostgreSQL</span>, refer to the
<a href="sql-grant.html">GRANT</a> reference
page. The following sections and chapters will also show you how
those privileges are used.
</p>
<p> The right to modify or destroy an object is always the privilege of
the owner only.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>
<p> To change the owner of a table, index, sequence, or view, use the
<a href="sql-altertable.html">ALTER TABLE</a>
command. There are corresponding <code class="literal">ALTER</code> commands for
other object types.
</p>
</div>
<p> To assign privileges, the <code class="command">GRANT</code> command is
used. For example, if <code class="literal">joe</code> is an existing user, and
<code class="literal">accounts</code> is an existing table, the privilege to
update the table can be granted with
</p>
<pre class="programlisting">GRANT UPDATE ON accounts TO joe;</pre>
<p>
To grant a privilege to a group, use this syntax:
</p>
<pre class="programlisting">GRANT SELECT ON accounts TO GROUP staff;</pre>
<p>
The special “<span class="quote">user</span>” name <code class="literal">PUBLIC</code> can
be used to grant a privilege to every user on the system. Writing
<code class="literal">ALL</code> in place of a specific privilege grants all
privileges that are relevant for the object type.
</p>
<p> To revoke a privilege, use the fittingly named
<code class="command">REVOKE</code> command:
</p>
<pre class="programlisting">REVOKE ALL ON accounts FROM PUBLIC;</pre>
<p>
The special privileges of the object owner (i.e., the right to do
<code class="command">DROP</code>, <code class="command">GRANT</code>, <code class="command">REVOKE</code>, 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.
</p>
<p> 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 “<span class="quote">with grant option</span>”, 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 <a href="sql-grant.html">GRANT</a> and <a href="sql-revoke.html">REVOKE</a> reference pages.
</p>
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