doc/src/sgml/ref/create_role.sgml - master - githubmirror/postgres

doc/src/sgml/ref/create_role.sgml
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Nathan Bossart
Deprecate MD5 passwords.
02 дек 2024, 22:30
02 дек 2024, 22:30db6a4a9
<!--
doc/src/sgml/ref/create_role.sgml
PostgreSQL documentation
-->

<refentry id="sql-createrole">
 <indexterm zone="sql-createrole">
  <primary>CREATE ROLE</primary>
 </indexterm>

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

 <refnamediv>
  <refname>CREATE ROLE</refname>
  <refpurpose>define a new database role</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
CREATE ROLE <replaceable class="parameter">name</replaceable> [ [ WITH ] <replaceable class="parameter">option</replaceable> [ ... ] ]

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

      SUPERUSER | NOSUPERUSER
    | CREATEDB | NOCREATEDB
    | CREATEROLE | NOCREATEROLE
    | INHERIT | NOINHERIT
    | LOGIN | NOLOGIN
    | REPLICATION | NOREPLICATION
    | BYPASSRLS | NOBYPASSRLS
    | CONNECTION LIMIT <replaceable class="parameter">connlimit</replaceable>
    | [ ENCRYPTED ] PASSWORD '<replaceable class="parameter">password</replaceable>' | PASSWORD NULL
    | VALID UNTIL '<replaceable class="parameter">timestamp</replaceable>'
    | IN ROLE <replaceable class="parameter">role_name</replaceable> [, ...]
    | ROLE <replaceable class="parameter">role_name</replaceable> [, ...]
    | ADMIN <replaceable class="parameter">role_name</replaceable> [, ...]
    | SYSID <replaceable class="parameter">uid</replaceable>
</synopsis>
 </refsynopsisdiv>

<!--
CAUTION: remember to keep create_user.sgml and create_group.sgml
in sync when changing the above synopsis!
-->

 <refsect1>
  <title>Description</title>

  <para>
   <command>CREATE ROLE</command> adds a new role to a
   <productname>PostgreSQL</productname> database cluster.  A role is
   an entity that can own database objects and have database privileges;
   a role can be considered a <quote>user</quote>, a <quote>group</quote>, or both
   depending on how it is used.  Refer to
   <xref linkend="user-manag"/> and <xref
   linkend="client-authentication"/> for information about managing
   users and authentication.  You must have <literal>CREATEROLE</literal>
   privilege or be a database superuser to use this command.
  </para>

  <para>
   Note that roles are defined at the database cluster
   level, and so are valid in all databases in the cluster.
  </para>

  <para>
   During role creation it is possible to immediately assign the newly created
   role to be a member of an existing role, and also assign existing roles
   to be members of the newly created role.  The rules for which initial
   role membership options are enabled are described below in the
   <literal>IN ROLE</literal>, <literal>ROLE</literal>, and
   <literal>ADMIN</literal> clauses.  The <xref linkend="sql-grant"/>
   command has fine-grained option control during membership creation,
   and the ability to modify these options after the new role is created.
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

    <variablelist>
     <varlistentry>
      <term><replaceable class="parameter">name</replaceable></term>
      <listitem>
       <para>
        The name of the new role.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><literal>SUPERUSER</literal></term>
      <term><literal>NOSUPERUSER</literal></term>
      <listitem>
       <para>
        These clauses determine whether the new role is a <quote>superuser</quote>,
        who can override all access restrictions within the database.
        Superuser status is dangerous and should be used only when really
        needed.  You must yourself be a superuser to create a new superuser.
        If not specified,
        <literal>NOSUPERUSER</literal> is the default.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><literal>CREATEDB</literal></term>
      <term><literal>NOCREATEDB</literal></term>
      <listitem>
       <para>
        These clauses define a role's ability to create databases.  If
        <literal>CREATEDB</literal> is specified, the role being
        defined will be allowed to create new databases. Specifying
        <literal>NOCREATEDB</literal> will deny a role the ability to
        create databases. If not specified,
        <literal>NOCREATEDB</literal> is the default.
        Only superuser roles or roles with <literal>CREATEDB</literal>
        can specify <literal>CREATEDB</literal>.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><literal>CREATEROLE</literal></term>
      <term><literal>NOCREATEROLE</literal></term>
      <listitem>
       <para>
        These clauses determine whether a role will be permitted to
        create, alter, drop, comment on, and change the security label for
        other roles.
        See <xref linkend="role-creation"/> for more details about what
        capabilities are conferred by this privilege.
        If not specified, <literal>NOCREATEROLE</literal> is the default.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><literal>INHERIT</literal></term>
      <term><literal>NOINHERIT</literal></term>
      <listitem>
       <para>
        This affects the membership inheritance status when this
        role is added as a member of another role, both in this and
        future commands.  Specifically, it controls the inheritance
        status of memberships added with this command using the
        <literal>IN ROLE</literal> clause, and in later commands using
        the <literal>ROLE</literal> clause.  It is also used as the
        default inheritance status when adding this role as a member
        using the <literal>GRANT</literal> command.  If not specified,
        <literal>INHERIT</literal> is the default.
       </para>

       <para>
        In <productname>PostgreSQL</productname> versions before 16,
        inheritance was a role-level attribute that controlled all runtime
        membership checks for that role.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><literal>LOGIN</literal></term>
      <term><literal>NOLOGIN</literal></term>
      <listitem>
       <para>
        These clauses determine whether a role is allowed to log in;
        that is, whether the role can be given as the initial session
        authorization name during client connection.  A role having
        the <literal>LOGIN</literal> attribute can be thought of as a user.
        Roles without this attribute are useful for managing database
        privileges, but are not users in the usual sense of the word.
        If not specified,
        <literal>NOLOGIN</literal> is the default, except when
        <command>CREATE ROLE</command> is invoked through its alternative spelling
        <link linkend="sql-createuser"><command>CREATE USER</command></link>.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><literal>REPLICATION</literal></term>
      <term><literal>NOREPLICATION</literal></term>
      <listitem>
       <para>
        These clauses determine whether a role is a replication role.  A role
        must have this attribute (or be a superuser) in order to be able to
        connect to the server in replication mode (physical or logical
        replication) and in order to be able to create or drop replication
        slots.
        A role having the <literal>REPLICATION</literal> attribute is a very
        highly privileged role, and should only be used on roles actually
        used for replication. If not specified,
        <literal>NOREPLICATION</literal> is the default.
        Only superuser roles or roles with <literal>REPLICATION</literal>
        can specify <literal>REPLICATION</literal>.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><literal>BYPASSRLS</literal></term>
      <term><literal>NOBYPASSRLS</literal></term>
      <listitem>
       <para>
        These clauses determine whether a role bypasses every row-level
        security (RLS) policy.  <literal>NOBYPASSRLS</literal> is the default.
        Only superuser roles or roles with <literal>BYPASSRLS</literal>
        can specify <literal>BYPASSRLS</literal>.
       </para>

       <para>
        Note that pg_dump will set <literal>row_security</literal> to
        <literal>OFF</literal> by default, to ensure all contents of a table are
        dumped out.  If the user running pg_dump does not have appropriate
        permissions, an error will be returned.  However, superusers and the
        owner of the table being dumped always bypass RLS.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><literal>CONNECTION LIMIT</literal> <replaceable class="parameter">connlimit</replaceable></term>
      <listitem>
       <para>
        If role can log in, this specifies how many concurrent connections
        the role can make.  -1 (the default) means no limit. Note that only
        normal connections are counted towards this limit. Neither prepared
        transactions nor background worker connections are counted towards
        this limit.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>[ <literal>ENCRYPTED</literal> ] <literal>PASSWORD</literal> '<replaceable class="parameter">password</replaceable>'</term>
      <term><literal>PASSWORD NULL</literal></term>
      <listitem>
       <para>
        Sets the role's password.  (A password is only of use for
        roles having the <literal>LOGIN</literal> attribute, but you
        can nonetheless define one for roles without it.)  If you do
        not plan to use password authentication you can omit this
        option.  If no password is specified, the password will be set
        to null and password authentication will always fail for that
        user.  A null password can optionally be written explicitly as
        <literal>PASSWORD NULL</literal>.
       </para>
       <note>
         <para>
           Specifying an empty string will also set the password to null,
           but that was not the case before <productname>PostgreSQL</productname>
           version 10. In earlier versions, an empty string could be used,
           or not, depending on the authentication method and the exact
           version, and libpq would refuse to use it in any case.
           To avoid the ambiguity, specifying an empty string should be
           avoided.
         </para>
       </note>
       <para>
        The password is always stored encrypted in the system catalogs. The
        <literal>ENCRYPTED</literal> keyword has no effect, but is accepted for
        backwards compatibility. The method of encryption is determined
        by the configuration parameter <xref linkend="guc-password-encryption"/>.
        If the presented password string is already in MD5-encrypted or
        SCRAM-encrypted format, then it is stored as-is regardless of
        <varname>password_encryption</varname> (since the system cannot decrypt
        the specified encrypted password string, to encrypt it in a
        different format).  This allows reloading of encrypted passwords
        during dump/restore.
       </para>
       <warning>
        <para>
         Support for MD5-encrypted passwords is deprecated and will be removed
         in a future release of <productname>PostgreSQL</productname>.  Refer
         to <xref linkend="auth-password"/> for details about migrating to
         another password type.
        </para>
       </warning>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><literal>VALID UNTIL</literal> '<replaceable class="parameter">timestamp</replaceable>'</term>
      <listitem>
       <para>
        The <literal>VALID UNTIL</literal> clause sets a date and
        time after which the role's password is no longer valid.  If
        this clause is omitted the password will be valid for all time.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><literal>IN ROLE</literal> <replaceable class="parameter">role_name</replaceable></term>
      <listitem>
       <para>
        The <literal>IN ROLE</literal> clause causes the new role to
        be automatically added as a member of the specified existing
        roles. The new membership will have the <literal>SET</literal>
        option enabled and the <literal>ADMIN</literal> option disabled.
        The <literal>INHERIT</literal> option will be enabled unless the
        <literal>NOINHERIT</literal> option is specified.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><literal>ROLE</literal> <replaceable class="parameter">role_name</replaceable></term>
      <listitem>
       <para>
        The <literal>ROLE</literal> clause causes one or more specified
        existing roles to be automatically added as members, with the
        <literal>SET</literal> option enabled. This in effect makes the
        new role a <quote>group</quote>.  Roles named in this clause
        with the role-level <literal>INHERIT</literal> attribute will have
        the <literal>INHERIT</literal> option enabled in the new membership.
        New memberships will have the <literal>ADMIN</literal> option disabled.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><literal>ADMIN</literal> <replaceable class="parameter">role_name</replaceable></term>
      <listitem>
       <para>
        The <literal>ADMIN</literal> clause has the same effect as
        <literal>ROLE</literal>, but the named roles are added as members
        of the new role with <literal>ADMIN</literal> enabled, giving
        them the right to grant membership in the new role to others.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><literal>SYSID</literal> <replaceable class="parameter">uid</replaceable></term>
      <listitem>
       <para>
        The <literal>SYSID</literal> clause is ignored, but is accepted
        for backwards compatibility.
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
 </refsect1>

 <refsect1>
  <title>Notes</title>

  <para>
   Use <link linkend="sql-alterrole"><command>ALTER ROLE</command></link> to
   change the attributes of a role, and <link linkend="sql-droprole"><command>DROP ROLE</command></link>
   to remove a role.  All the attributes
   specified by <command>CREATE ROLE</command> can be modified by later
   <command>ALTER ROLE</command> commands.
  </para>

  <para>
   The preferred way to add and remove members of roles that are being
   used as groups is to use
   <link linkend="sql-grant"><command>GRANT</command></link> and
   <link linkend="sql-revoke"><command>REVOKE</command></link>.
  </para>

  <para>
   The <literal>VALID UNTIL</literal> clause defines an expiration time for a
   password only, not for the role per se.  In
   particular, the expiration time is not enforced when logging in using
   a non-password-based authentication method.
  </para>

  <para>
   The role attributes defined here are non-inheritable, i.e., being a
   member of a role with, e.g., <literal>CREATEDB</literal> will not
   allow the member to create new databases even if the membership grant
   has the <literal>INHERIT</literal> option.  Of course, if the membership
   grant has the <literal>SET</literal> option the member role would be able to
   <link linkend="sql-set-role"><command>SET ROLE</command></link> to the
   createdb role and then create a new database.
  </para>

  <para>
   The membership grants created by the
   <literal>IN ROLE</literal>, <literal>ROLE</literal>, and <literal>ADMIN</literal>
   clauses have the role executing this command as the grantor.
  </para>

  <para>
   The <literal>INHERIT</literal> attribute is the default for reasons of backwards
   compatibility: in prior releases of <productname>PostgreSQL</productname>,
   users always had access to all privileges of groups they were members of.
   However, <literal>NOINHERIT</literal> provides a closer match to the semantics
   specified in the SQL standard.
  </para>

  <para>
   <productname>PostgreSQL</productname> includes a program <xref
   linkend="app-createuser"/> that has
   the same functionality as <command>CREATE ROLE</command> (in fact,
   it calls this command) but can be run from the command shell.
  </para>

  <para>
   The <literal>CONNECTION LIMIT</literal> option is only enforced approximately;
   if two new sessions start at about the same time when just one
   connection <quote>slot</quote> remains for the role, it is possible that
   both will fail.  Also, the limit is never enforced for superusers.
  </para>

  <para>
   Caution must be exercised when specifying an unencrypted password
   with this command.  The password will be transmitted to the server
   in cleartext, and it might also be logged in the client's command
   history or the server log.  The command <xref
   linkend="app-createuser"/>, however, transmits
   the password encrypted.  Also, <xref linkend="app-psql"/>
   contains a command
   <command>\password</command> that can be used to safely change the
   password later.
  </para>
 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   Create a role that can log in, but don't give it a password:
<programlisting>
CREATE ROLE jonathan LOGIN;
</programlisting>
  </para>

  <para>
   Create a role with a password:
<programlisting>
CREATE USER davide WITH PASSWORD 'jw8s0F4';
</programlisting>
   (<command>CREATE USER</command> is the same as <command>CREATE ROLE</command> except
   that it implies <literal>LOGIN</literal>.)
  </para>

  <para>
   Create a role with a password that is valid until the end of 2004.
   After one second has ticked in 2005, the password is no longer
   valid.

<programlisting>
CREATE ROLE miriam WITH LOGIN PASSWORD 'jw8s0F4' VALID UNTIL '2005-01-01';
</programlisting>
  </para>

  <para>
   Create a role that can create databases and manage roles:
<programlisting>
CREATE ROLE admin WITH CREATEDB CREATEROLE;
</programlisting></para>
 </refsect1>

 <refsect1>
  <title>Compatibility</title>

  <para>
   The <command>CREATE ROLE</command> statement is in the SQL standard,
   but the standard only requires the syntax
<synopsis>
CREATE ROLE <replaceable class="parameter">name</replaceable> [ WITH ADMIN <replaceable class="parameter">role_name</replaceable> ]
</synopsis>
   Multiple initial administrators, and all the other options of
   <command>CREATE ROLE</command>, are
   <productname>PostgreSQL</productname> extensions.
  </para>

  <para>
   The SQL standard defines the concepts of users and roles, but it
   regards them as distinct concepts and leaves all commands defining
   users to be specified by each database implementation.  In
   <productname>PostgreSQL</productname> we have chosen to unify
   users and roles into a single kind of entity.  Roles therefore
   have many more optional attributes than they do in the standard.
  </para>

  <para>
   The behavior specified by the SQL standard is most closely approximated
   creating SQL-standard users as <productname>PostgreSQL</productname>
   roles with the <literal>NOINHERIT</literal> option, and SQL-standard
   roles as <productname>PostgreSQL</productname> roles with the
   <literal>INHERIT</literal> option.
  </para>

  <para>
   The <literal>USER</literal> clause has the same behavior as
   <literal>ROLE</literal> but has been deprecated:
<synopsis>
USER <replaceable class="parameter">role_name</replaceable> [, ...]
</synopsis>
  </para>

  <para>
   The <literal>IN GROUP</literal> clause has the same behavior as <literal>IN
   ROLE</literal> but has been deprecated:
<synopsis>
IN GROUP <replaceable class="parameter">role_name</replaceable> [, ...]
</synopsis>
  </para>
 </refsect1>

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

  <simplelist type="inline">
   <member><xref linkend="sql-set-role"/></member>
   <member><xref linkend="sql-alterrole"/></member>
   <member><xref linkend="sql-droprole"/></member>
   <member><xref linkend="sql-grant"/></member>
   <member><xref linkend="sql-revoke"/></member>
   <member><xref linkend="app-createuser"/></member>
   <member><xref linkend="guc-createrole-self-grant"/></member>
  </simplelist>
 </refsect1>
</refentry>