mirror of https://github.com/postgres/postgres
Peter Eisentraut
25 years ago
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<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/set_session_auth.sgml,v 1.1 2001/05/08 21:06:42 petere Exp $ --> |
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<refentry id="SQL-SET-SESSION-AUTHORIZATION"> |
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<docinfo> |
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<date>2001-04-21</date> |
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</docinfo> |
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|
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<refmeta> |
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<refentrytitle>SET SESSION AUTHORIZATION</refentrytitle> |
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<refmiscinfo>SQL - Language Statements</refmiscinfo> |
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</refmeta> |
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|
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<refnamediv> |
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<refname>SET SESSION AUTHORIZATION</refname> |
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<refpurpose>Set the session user identifier and the current user identifier |
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of the current SQL-session context</refpurpose> |
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</refnamediv> |
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|
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<refsynopsisdiv> |
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<synopsis> |
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SET SESSION AUTHORIZATION '<parameter>username</parameter>' |
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</synopsis> |
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</refsynopsisdiv> |
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|
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<refsect1> |
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<title>Description</title> |
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|
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<para> |
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This command sets the session user identifier and the current user |
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identifer of the current SQL-session context to be |
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<parameter>username</parameter>. |
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</para> |
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|
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<para> |
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The session user identifier is initially set to be the (possibly |
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authenticated) user name provided by the client. The current user |
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identifier is normally equal to the session user identifier, but |
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may change temporarily in the context of <quote>setuid</quote> |
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functions and similar mechanisms. The current user identifer is |
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relevant for permission checking. |
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</para> |
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|
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<para> |
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Execution of this command is only permitted if the initial session |
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user (the <firstterm>authenticated user</firstterm>) had the |
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superuser privilege. This permission is kept for the duration of a |
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connection; for example, it is possible to temporarily become an |
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unprivileged user and later switch back to become a superuser. |
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</para> |
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</refsect1> |
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|
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<refsect1> |
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<title>Examples</title> |
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|
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<screen> |
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<userinput>SELECT SESSION_USER, CURRENT_USER;</userinput> |
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current_user | session_user |
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--------------+-------------- |
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peter | peter |
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|
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<userinput>SET SESSION AUTHORIZATION 'paul';</userinput> |
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|
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<userinput>SELECT SESSION_USER, CURRENT_USER;</userinput> |
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current_user | session_user |
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--------------+-------------- |
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paul | paul |
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</screen> |
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</refsect1> |
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|
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<refsect1> |
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<title>Compatibility</title> |
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<simpara>SQL99</simpara> |
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<para> |
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SQL99 allows some other expressions to appear in place of the |
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literal <parameter>username</parameter> which are not important in |
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practice. <application>PostgreSQL</application> allows identifier |
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syntax (<literal>"username"</literal>), which SQL does not. SQL |
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does not allow this command during a transaction; |
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<application>PostgreSQL</application> does not make |
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this restriction because there is no reason to. The |
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privileges necessary to execute this command are left |
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implementation-defined by the standard. |
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</para> |
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</refsect1> |
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</refentry> |
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|
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<!-- Keep this comment at the end of the file |
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Local variables: |
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mode:sgml |
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sgml-omittag:nil |
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sgml-shorttag:t |
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sgml-minimize-attributes:nil |
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sgml-always-quote-attributes:t |
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sgml-indent-step:1 |
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sgml-indent-data:t |
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sgml-parent-document:nil |
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sgml-default-dtd-file:"../reference.ced" |
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sgml-exposed-tags:nil |
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sgml-local-catalogs:("/usr/lib/sgml/catalog") |
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sgml-local-ecat-files:nil |
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End: |
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--> |
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