value of a null pointer, in which case it will return
        <symbol>PGRES_FATAL_ERROR</symbol>).  Use
        <xref linkend="libpq-PQerrorMessage"/> to get more information about such
        errors.
       </para>
      </listitem>
     </varlistentry>
    </variablelist>

    The command string can include multiple SQL commands
    (separated by semicolons).  Multiple queries sent in a single
    <xref linkend="libpq-PQexec"/> call are processed in a single transaction, unless
    there are explicit <command>BEGIN</command>/<command>COMMIT</command>
    commands included in the query string to divide it into multiple
    transactions.  (See <xref linkend="protocol-flow-multi-statement"/>
    for more details about how the server handles multi-query strings.)
    Note however that the returned
    <structname>PGresult</structname> structure describes only the result
    of the last command executed from the string.  Should one of the
    commands fail, processing of the string stops with it and the returned
    <structname>PGresult</structname> describes the error condition.
   </para>

   <para>
    <variablelist>
     <varlistentry id="libpq-PQexecParams">
      <term><function>PQexecParams</function><indexterm><primary>PQexecParams</primary></indexterm></term>

      <listitem>
       <para>
        Submits a command to the server and waits for the result,
        with the ability to pass parameters separately from the SQL
        command text.

<synopsis>
PGresult *PQexecParams(PGconn *conn,
                       const char *command,
                       int nParams,
                       const Oid *paramTypes,
                       const char * const *paramValues,
                       const int *paramLengths,
                       const int *paramFormats,
                       int resultFormat);
</synopsis>
       </para>

       <para>
        <xref linkend="libpq-PQexecParams"/> is like <xref linkend="libpq-PQexec"/>, but offers additional
        functionality: parameter values can be specified separately from the command
        string proper, and query results can be requested in either text or binary
        format.
       </para>

       <para>
        The function arguments are:

        <variablelist>
         <varlistentry>
          <term><parameter>conn</parameter></term>

          <listitem>
           <para>
            The connection object to send the command through.
           </para>
          </listitem>
         </varlistentry>

         <varlistentry>
          <term><parameter>command</parameter></term>
          <listitem>
           <para>
            The SQL command string to be executed. If parameters are used,
            they are referred to in the command string as <literal>$1</literal>,
            <literal>$2</literal>, etc.
           </para>
          </listitem>
         </varlistentry>

         <varlistentry>
          <term><parameter>nParams</parameter></term>
          <listitem>
           <para>
            The number of parameters supplied; it is the length of the arrays
            <parameter>paramTypes[]</parameter>, <parameter>paramValues[]</parameter>,
            <parameter>paramLengths[]</parameter>, and <parameter>paramFormats[]</parameter>. (The
            array pointers can be <symbol>NULL</symbol> when <parameter>nParams</parameter>
            is zero.)
           </para>
          </listitem>
         </varlistentry>

         <varlistentry>
          <term><parameter>paramTypes[]</parameter></term>
          <listitem>
           <para>
            Specifies, by OID, the data types to be assigned to the
            parameter symbols.  If <parameter>paramTypes</parameter> is
            <symbol>NULL</symbol>, or any particular element in the array
            is zero, the server infers a data type for the parameter symbol
            in the same way it would do for an untyped literal string.
           </para>
          </listitem>
         </varlistentry>