close.sgml

postgresql8.3.4源码,开源数据库

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$PostgreSQL: pgsql/doc/src/sgml/ref/close.sgml,v 1.26 2007/05/15 19:13:55 neilc Exp $
PostgreSQL documentation
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<refentry id="SQL-CLOSE">
 <refmeta>
  <refentrytitle id="SQL-CLOSE-TITLE">CLOSE</refentrytitle>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>CLOSE</refname>
  <refpurpose>close a cursor</refpurpose>
 </refnamediv>

 <indexterm zone="sql-close">
  <primary>CLOSE</primary>
 </indexterm>

 <indexterm zone="sql-close">
  <primary>cursor</primary>
  <secondary>CLOSE</secondary>
 </indexterm>

 <refsynopsisdiv>
<synopsis>
CLOSE { <replaceable class="PARAMETER">name</replaceable> | ALL }
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>CLOSE</command> frees the resources associated with an open cursor.
   After the cursor is closed, no subsequent operations
   are allowed on it. A cursor should be closed when it is
   no longer needed.
  </para>

  <para>
   Every non-holdable open cursor is implicitly closed when a
   transaction is terminated by <command>COMMIT</command> or
   <command>ROLLBACK</command>.  A holdable cursor is implicitly
   closed if the transaction that created it aborts via
   <command>ROLLBACK</command>.  If the creating transaction
   successfully commits, the holdable cursor remains open until an
   explicit <command>CLOSE</command> is executed, or the client
   disconnects.
  </para>
 </refsect1>
  
 <refsect1>
  <title>Parameters</title>

  <variablelist>
   <varlistentry>
    <term><replaceable class="PARAMETER">name</replaceable></term>
    <listitem>
     <para>
      The name of an open cursor to close.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>ALL</literal></term>
    <listitem>
     <para>
      Close all open cursors.
     </para>
    </listitem>
   </varlistentry>

  </variablelist>
 </refsect1>

 <refsect1>
  <title>Notes</title>

  <para>
   <productname>PostgreSQL</productname> does not have an explicit
   <command>OPEN</command> cursor statement; a cursor is considered
   open when it is declared.  Use the
   <xref linkend="sql-declare" endterm="sql-declare-title">
   statement to declare a cursor.
  </para>

  <para>
   You can see all available cursors by querying the <link
   linkend="view-pg-cursors"><structname>pg_cursors</></> system view.
  </para>
 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   Close the cursor <literal>liahona</literal>:
<programlisting>
CLOSE liahona;
</programlisting>
  </para>
 </refsect1>
 
 <refsect1>
  <title>Compatibility</title>
  
  <para>
   <command>CLOSE</command> is fully conforming with the SQL
   standard. <command>CLOSE ALL</> is a <productname>PostgreSQL</>
   extension.
  </para>
 </refsect1>

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

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