= f (type: 1)
datconnlimit = -1 (type: 5)
datfrozenxid = 379 (type: 1)
dattablespace = 1663 (type: 1)
datconfig =  (type: 1)
datacl =  (type: 1)
datid = 11511 (type: 1)
datname = postgres (type: 1)
numbackends = 0 (type: 5)
xact_commit = 221069 (type: 9)
xact_rollback = 18 (type: 9)
blks_read = 1176 (type: 9)
blks_hit = 13943750 (type: 9)
tup_returned = 77410091 (type: 9)
tup_fetched = 3253694 (type: 9)
tup_inserted = 0 (type: 9)
tup_updated = 0 (type: 9)
tup_deleted = 0 (type: 9)
</screen>
    </example>
   </sect3>
  </sect2>
 </sect1>

 <sect1 id="ecpg-errors">
  <title>Error Handling</title>

  <para>
   This section describes how you can handle exceptional conditions
   and warnings in an embedded SQL program.  There are two
   nonexclusive facilities for this.

   <itemizedlist>
    <listitem>
     <simpara>
      Callbacks can be configured to handle warning and error
      conditions using the <literal>WHENEVER</literal> command.
     </simpara>
    </listitem>

    <listitem>
     <simpara>
      Detailed information about the error or warning can be obtained
      from the <varname>sqlca</varname> variable.
     </simpara>
    </listitem>
   </itemizedlist>
  </para>

  <sect2 id="ecpg-whenever">
   <title>Setting Callbacks</title>

   <para>
    One simple method to catch errors and warnings is to set a
    specific action to be executed whenever a particular condition
    occurs.  In general:
<programlisting>
EXEC SQL WHENEVER <replaceable>condition</replaceable> <replaceable>action</replaceable>;
</programlisting>
   </para>

   <para>
    <replaceable>condition</replaceable> can be one of the following:

    <variablelist>
     <varlistentry id="ecpg-whenever-sqlerror">
      <term><literal>SQLERROR</literal></term>
      <listitem>
       <para>
        The specified action is called whenever an error occurs during
        the execution of an SQL statement.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="ecpg-whenever-sqlwarning">
      <term><literal>SQLWARNING</literal></term>
      <listitem>
       <para>
        The specified action is called whenever a warning occurs
        during the execution of an SQL statement.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="ecpg-whenever-not-found">
      <term><literal>NOT FOUND</literal></term>
      <listitem>
       <para>
        The specified action is called whenever an SQL statement
        retrieves or affects zero rows.  (This condition is not an
        error, but you might be interested in handling it specially.)
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
   </para>

   <para>
    <replaceable>action</replaceable> can be one of the following:

    <variablelist>
     <varlistentry id="ecpg-whenever-continue">
      <term><literal>CONTINUE</literal></term>
      <listitem>
       <para>
        This effectively means that the condition is ignored.  This is
        the default.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="ecpg-whenever-goto">
      <term><literal>GOTO <replaceable>label</replaceable></literal></term>
      <term><literal>GO TO <replaceable>label</replaceable></literal></term>
      <listitem>
       <para>
        Jump to the specified label (using a C <literal>goto</literal>
        statement).
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="ecpg-whenever-sqlprint">
      <term><literal>SQLPRINT</literal></term>
      <listitem>
       <para>
        Print a message to standard error.  This is useful for simple
        programs or during prototyping.  The details of the message
        cannot be configured.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="ecpg-whenever-stop">
      <term><literal>STOP</literal></term>
      <listitem>
       <para>
        Call <literal>exit(1)</literal>, which will terminate the
        program.
       </para>
      </listitem>