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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>22.1. Database Roles</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="user-manag.html" title="Chapter 22. Database Roles" /><link rel="next" href="role-attributes.html" title="22.2. Role Attributes" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">22.1. Database Roles</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="user-manag.html" title="Chapter 22. Database Roles">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="user-manag.html" title="Chapter 22. Database Roles">Up</a></td><th width="60%" align="center">Chapter 22. Database Roles</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.3 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="role-attributes.html" title="22.2. Role Attributes">Next</a></td></tr></table><hr /></div><div class="sect1" id="DATABASE-ROLES"><div class="titlepage"><div><div><h2 class="title" style="clear: both">22.1. Database Roles <a href="#DATABASE-ROLES" class="id_link">#</a></h2></div></div></div><a id="id-1.6.9.5.2" class="indexterm"></a><a id="id-1.6.9.5.3" class="indexterm"></a><a id="id-1.6.9.5.4" class="indexterm"></a><a id="id-1.6.9.5.5" class="indexterm"></a><p>
Database roles are conceptually completely separate from
operating system users. In practice it might be convenient to
maintain a correspondence, but this is not required. Database roles
are global across a database cluster installation (and not
per individual database). To create a role use the <a class="link" href="sql-createrole.html" title="CREATE ROLE"><code class="command">CREATE ROLE</code></a> SQL command:
</p><pre class="synopsis">
CREATE ROLE <em class="replaceable"><code>name</code></em>;
</pre><p>
<em class="replaceable"><code>name</code></em> follows the rules for SQL
identifiers: either unadorned without special characters, or
double-quoted. (In practice, you will usually want to add additional
options, such as <code class="literal">LOGIN</code>, to the command. More details appear
below.) To remove an existing role, use the analogous
<a class="link" href="sql-droprole.html" title="DROP ROLE"><code class="command">DROP ROLE</code></a> command:
</p><pre class="synopsis">
DROP ROLE <em class="replaceable"><code>name</code></em>;
</pre><p>
</p><a id="id-1.6.9.5.7" class="indexterm"></a><a id="id-1.6.9.5.8" class="indexterm"></a><p>
For convenience, the programs <a class="xref" href="app-createuser.html" title="createuser"><span class="refentrytitle"><span class="application">createuser</span></span></a>
and <a class="xref" href="app-dropuser.html" title="dropuser"><span class="refentrytitle"><span class="application">dropuser</span></span></a> are provided as wrappers
around these SQL commands that can be called from the shell command
line:
</p><pre class="synopsis">
createuser <em class="replaceable"><code>name</code></em>
dropuser <em class="replaceable"><code>name</code></em>
</pre><p>
</p><p>
To determine the set of existing roles, examine the <code class="structname">pg_roles</code>
system catalog, for example:
</p><pre class="synopsis">
SELECT rolname FROM pg_roles;
</pre><p>
or to see just those capable of logging in:
</p><pre class="synopsis">
SELECT rolname FROM pg_roles WHERE rolcanlogin;
</pre><p>
The <a class="xref" href="app-psql.html" title="psql"><span class="refentrytitle"><span class="application">psql</span></span></a> program's <code class="literal">\du</code> meta-command
is also useful for listing the existing roles.
</p><p>
In order to bootstrap the database system, a freshly initialized
system always contains one predefined login-capable role. This role
is always a <span class="quote">“<span class="quote">superuser</span>”</span>, and it will have
the same name as the operating system user that initialized the
database cluster with <code class="command">initdb</code> unless a different name
is specified. This role is often named
<code class="literal">postgres</code>. In order to create more roles you
first have to connect as this initial role.
</p><p>
Every connection to the database server is made using the name of some
particular role, and this role determines the initial access privileges for
commands issued in that connection.
The role name to use for a particular database
connection is indicated by the client that is initiating the
connection request in an application-specific fashion. For example,
the <code class="command">psql</code> program uses the
<code class="option">-U</code> command line option to indicate the role to
connect as. Many applications assume the name of the current
operating system user by default (including
<code class="command">createuser</code> and <code class="command">psql</code>). Therefore it
is often convenient to maintain a naming correspondence between
roles and operating system users.
</p><p>
The set of database roles a given client connection can connect as
is determined by the client authentication setup, as explained in
<a class="xref" href="client-authentication.html" title="Chapter 21. Client Authentication">Chapter 21</a>. (Thus, a client is not
limited to connect as the role matching
its operating system user, just as a person's login name
need not match his or her real name.) Since the role
identity determines the set of privileges available to a connected
client, it is important to carefully configure privileges when setting up
a multiuser environment.
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