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$PostgreSQL: pgsql/doc/src/sgml/ref/do.sgml,v 1.5 2010/02/16 00:49:42 itagaki Exp $
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<refentry id="SQL-DO">
 <refmeta>
  <refentrytitle id="sql-do-title">DO</refentrytitle>
  <manvolnum>7</manvolnum>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>DO</refname>
  <refpurpose>execute an anonymous code block</refpurpose>
 </refnamediv>

 <indexterm zone="sql-do">
  <primary>DO</primary>
 </indexterm>

 <indexterm zone="sql-do">
  <primary>anonymous code blocks</primary>
 </indexterm>

 <refsynopsisdiv>
<synopsis>
DO [ LANGUAGE <replaceable class="PARAMETER">lang_name</replaceable> ] <replaceable class="PARAMETER">code</replaceable>
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>DO</command> executes an anonymous code block, or in other
   words a transient anonymous function in a procedural language.
  </para>

  <para>
   The code block is treated as though it were the body of a function
   with no parameters, returning <type>void</>.  It is parsed and
   executed a single time.
  </para>

  <para>
   The optional <literal>LANGUAGE</> clause can be written either
   before or after the code block.
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

  <variablelist>
   <varlistentry>
    <term><replaceable class="PARAMETER">code</replaceable></term>
    <listitem>
     <para>
      The procedural language code to be executed.  This must be specified
      as a string literal, just as in <command>CREATE FUNCTION</>.
      Use of a dollar-quoted literal is recommended.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="PARAMETER">lang_name</replaceable></term>
    <listitem>
     <para>
      The name of the procedural language the code is written in.
      If omitted, the default is <literal>plpgsql</>.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1>
  <title>Notes</title>

  <para>
   The procedural language to be used must already have been installed
   into the current database by means of <command>CREATE LANGUAGE</>.
   <literal>plpgsql</> is installed by default, but other languages are not.
  </para>

  <para>
   The user must have <literal>USAGE</> privilege for the procedural
   language, or must be a superuser if the language is untrusted.
   This is the same privilege requirement as for creating a function
   in the language.
  </para>
 </refsect1>

 <refsect1 id="sql-do-examples">
  <title id="sql-do-examples-title">Examples</title>
  <para>
   Grant all privileges on all views in schema <literal>public</> to
   role <literal>webuser</>:
<programlisting>
DO $$DECLARE r record;
BEGIN
    FOR r IN SELECT table_schema, table_name FROM information_schema.tables
             WHERE table_type = 'VIEW' AND table_schema = 'public'
    LOOP
        EXECUTE 'GRANT ALL ON ' || quote_ident(r.table_schema) || '.' || quote_ident(r.table_name) || ' TO webuser';
    END LOOP;
END$$;
</programlisting>
  </para>
 </refsect1>
 <refsect1>
  <title>Compatibility</title>

  <para>
   There is no <command>DO</command> statement in the SQL standard.
  </para>
 </refsect1>

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

  <simplelist type="inline">
   <member><xref linkend="sql-createlanguage" endterm="sql-createlanguage-title"></member>
  </simplelist>
 </refsect1>
</refentry>
