php-doc-en/reference/mysqli/functions/mysqli-stmt-result-metadata.xml

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<refentry id="function.mysqli-stmt-result-metadata">
 <refnamediv>
  <refname>mysqli_stmt_result_metadata</refname>
  <refpurpose>Returns result set metadata from a prepared statement</refpurpose>
 </refnamediv>
 <refsect1>
  <title>Description</title>
  <para>Procedural style:</para>
  <methodsynopsis>
   <type>mixed</type><methodname>mysqli_stmt_result_metadata</methodname>
   <methodparam><type>mysqli_stmt</type><parameter>stmt</parameter></methodparam>
  </methodsynopsis>
  <para>Object oriented style (method):</para>
  <classsynopsis>
   <ooclass><classname>mysqli_stmt</classname></ooclass>
   <methodsynopsis>
    <type>mixed</type><methodname>result_metadata</methodname>
    <void />
   </methodsynopsis>
  </classsynopsis>     
  <para>
   If a statement passed to <function>mysqli_prepare</function> is one that produces
   a result set, <function>mysqli_stmt_result_metadata</function> returns the result object 
   that can be used to process the meta information such as total number of fields 
   and individual field information. 
  </para>
  <note>
   <para>This result set pointer can be passed as an argument to any of the 
    field-based functions that process result set metadata, such as: 
    <itemizedlist>
     <listitem><para><function>mysqli_num_fields</function></para></listitem>
     <listitem><para><function>mysqli_fetch_field</function></para></listitem>
     <listitem><para><function>mysqli_fetch_field_direct</function></para></listitem>
     <listitem><para><function>mysqli_fetch_fields</function></para></listitem>
     <listitem><para><function>mysqli_field_count</function></para></listitem>
     <listitem><para><function>mysqli_field_seek</function></para></listitem>
     <listitem><para><function>mysqli_field_tell</function></para></listitem>
     <listitem><para><function>mysqli_free_result</function></para></listitem>
    </itemizedlist>
   </para>
  </note>
  <para>
   The result set structure should be freed when you are done with it, 
   which you can do by passing it to <function>mysqli_free_result</function>
  </para>
  <note>
   <para>
    The result set returned by <function>mysqli_stmt_result_metadata</function> contains only 
    metadata. It does not contain any row results. The rows are obtained by using the
    statement handle with <function>mysqli_stmt_fetch</function>.
   </para> 
  </note>
 </refsect1>
 <refsect1>
  &reftitle.returnvalues;
  <para>
   <function>mysqli_stmt_result_metadata</function> returns a result object or &false; if
   an error occured.
  </para>
 </refsect1>
 <refsect1>
  &reftitle.seealso;
  <para>
   <function>mysqli_prepare</function>&listendand;
   <function>mysqli_free_result</function>.
  </para>
 </refsect1>
 <refsect1>
  &reftitle.examples;
  <para>
   <example>
    <title>Object oriented style</title>
    <programlisting role='php'>
<![CDATA[
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "test");

$mysqli->query("DROP TABLE IF EXISTS friends"); 
$mysqli->query("CREATE TABLE friends (id int, name varchar(20))"); 
 
$mysqli->query("INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')");

$stmt = $mysqli->prepare("SELECT id, name FROM friends");
$stmt->execute();

/* get resultset for metadata */
$result = $stmt->result_metadata();

/* retrieve field information from metadata result set */
$field = $result->fetch_field();

printf("Fieldname: %s\n", $field->name);

/* close resultset */
$result->close();

/* close connection */
$mysqli->close();
?>
]]>
    </programlisting>
   </example>
   <example>
    <title>Procedural style</title>
    <programlisting role='php'>
<![CDATA[
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "test");

mysqli_query($link, "DROP TABLE IF EXISTS friends"); 
mysqli_query($link, "CREATE TABLE friends (id int, name varchar(20))"); 
 
mysqli_query($link, "INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')");

$stmt = mysqli_prepare($link, "SELECT id, name FROM friends");
mysqli_stmt_execute($stmt);

/* get resultset for metadata */
$result = mysqli_stmt_result_metadata($stmt);

/* retrieve field information from metadata result set */
$field = mysqli_fetch_field($result);

printf("Fieldname: %s\n", $field->name);

/* close resultset */
mysqli_free_result($result);

/* close connection */
mysqli_close($link);
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>
</refentry>

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