<simpara>
      <literal><replaceable>connection-name</replaceable></literal>
     </simpara>
    </listitem>

    <listitem>
     <simpara>
      <literal>CURRENT</literal>
     </simpara>
    </listitem>

    <listitem>
     <simpara>
      <literal>ALL</literal>
     </simpara>
    </listitem>
   </itemizedlist>

   If no connection name is specified, the current connection is
   closed.
  </para>

  <para>
   It is good style that an application always explicitly disconnect
   from every connection it opened.
  </para>
  </sect2>

 </sect1>

 <sect1 id="ecpg-commands">
  <title>Running SQL Commands</title>

  <para>
   Any SQL command can be run from within an embedded SQL application.
   Below are some examples of how to do that.
  </para>

  <sect2 id="ecpg-executing">
   <title>Executing SQL Statements</title>

  <para>
   Creating a table:
<programlisting>
EXEC SQL CREATE TABLE foo (number integer, ascii char(16));
EXEC SQL CREATE UNIQUE INDEX num1 ON foo(number);
EXEC SQL COMMIT;
</programlisting>
  </para>

  <para>
   Inserting rows:
<programlisting>
EXEC SQL INSERT INTO foo (number, ascii) VALUES (9999, 'doodad');
EXEC SQL COMMIT;
</programlisting>
  </para>

  <para>
   Deleting rows:
<programlisting>
EXEC SQL DELETE FROM foo WHERE number = 9999;
EXEC SQL COMMIT;
</programlisting>
  </para>

  <para>
   Updates:
<programlisting>
EXEC SQL UPDATE foo
    SET ascii = 'foobar'
    WHERE number = 9999;
EXEC SQL COMMIT;
</programlisting>
  </para>

  <para>
   <literal>SELECT</literal> statements that return a single result
   row can also be executed using
   <literal>EXEC SQL</literal> directly.  To handle result sets with
   multiple rows, an application has to use a cursor;
   see <xref linkend="ecpg-cursors"/> below.  (As a special case, an
   application can fetch multiple rows at once into an array host
   variable; see <xref linkend="ecpg-variables-arrays"/>.)
  </para>

  <para>
   Single-row select:
<programlisting>
EXEC SQL SELECT foo INTO :FooBar FROM table1 WHERE ascii = 'doodad';
</programlisting>
  </para>

  <para>
   Also, a configuration parameter can be retrieved with the
   <literal>SHOW</literal> command:
<programlisting>
EXEC SQL SHOW search_path INTO :var;
</programlisting>
  </para>

  <para>
   The tokens of the form
   <literal>:<replaceable>something</replaceable></literal> are
   <firstterm>host variables</firstterm>, that is, they refer to
   variables in the C program.  They are explained in <xref
   linkend="ecpg-variables"/>.
  </para>
  </sect2>

  <sect2 id="ecpg-cursors">
   <title>Using Cursors</title>

  <para>
   To retrieve a result set holding multiple rows, an application has
   to declare a cursor and fetch each row from the cursor.  The steps
   to use a cursor are the following: declare a cursor, open it, fetch
   a row from the cursor, repeat, and finally close it.
  </para>

  <para>
   Select using cursors:
<programlisting>
EXEC SQL DECLARE foo_bar CURSOR FOR
    SELECT number, ascii FROM foo
    ORDER BY ascii;
EXEC SQL OPEN foo_bar;
EXEC SQL FETCH foo_bar INTO :FooBar, DooDad;
...
EXEC SQL CLOSE foo_bar;
EXEC SQL COMMIT;
</programlisting>
  </para>

  <para>
   For more details about declaring a cursor, see <xref
   linkend="ecpg-sql-declare"/>; for more details about fetching rows from a
   cursor, see <xref linkend="sql-fetch"/>.
  </para>

   <note>
    <para>
     The ECPG <command>DECLARE</command> command does not actually
     cause a statement to be sent to the PostgreSQL backend.  The
     cursor is opened in the backend (using the
     backend's <command>DECLARE</command> command) at the point when
     the <command>OPEN</command> command is executed.
    </para>
   </note>
  </sect2>

  <sect2 id="ecpg-transactions">
   <title>Managing Transactions</title>

  <para>
   In the default mode, statements are committed only when
   <command>EXEC SQL COMMIT</command> is issued. The embedded SQL
   interface also supports autocommit of transactions (similar to