php-doc-en/reference/pdo/functions/PDOStatement-getColumnMeta.xml

<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.7 $ -->
<refentry id="function.PDOStatement-getColumnMeta">
 <refnamediv>
  <refname>PDOStatement->getColumnMeta()</refname>
  <refpurpose>
   Returns metadata for a column in a result set
  </refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <classsynopsis>
   <ooclass><classname>PDOStatement</classname></ooclass>
   <methodsynopsis>
    <type>mixed</type><methodname>getColumnMeta</methodname>
    <methodparam><type>int</type><parameter>column</parameter></methodparam>
   </methodsynopsis>
  </classsynopsis>

  &warn.experimental.func;
  <para>
   Retrieves the metadata for a 0-indexed column in a result set as an
   associative array.
  </para>
  <warning>
   <simpara>
    Not all PDO drivers support
    <xref linkend="function.PDOStatement-getColumnMeta" />.
   </simpara>
  </warning>

 </refsect1>
 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>column</parameter></term>
      <listitem>
       <para>
        The 0-indexed column in the result set.
       </para>
      </listitem>
     </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns an associative array containing the following values representing
   the metadata for a single column:
  </para>
   <table>
    <title>Column metadata</title>
    <tgroup cols='2'>
     <colspec colname='c1'/> 
     <colspec colname='c2'/> 
     <thead>
      <row>
       <entry>Name</entry>
       <entry>Value</entry>
      </row>
     </thead>
     <tbody>
      <row>
       <entry><literal>native_type</literal></entry>
       <entry>The PHP native type used to represent the column value.</entry>
      </row>
      <row>
       <entry><literal><varname>driver</varname>:decl_type</literal></entry>
       <entry>The SQL type used to represent the column value in the database.
       If the column in the result set is the result of a function, this value
       is not returned by <xref linkend="function.PDOStatement-getColumnMeta" />.
       </entry>
      </row>
      <row>
       <entry><literal>flags</literal></entry>
       <entry>Any flags set for this column.</entry>
      </row>
      <row>
       <entry><literal>name</literal></entry>
       <entry>The name of this column as returned by the database.</entry>
      </row>
      <row>
       <entry><literal>len</literal></entry>
       <entry>The length of this column. Normally <literal>-1</literal> for
       types other than floating point decimals.</entry>
      </row>
      <row>
       <entry><literal>precision</literal></entry>
       <entry>The numeric precision of this column. Normally
       <literal>0</literal> for types other than floating point
       decimals.</entry>
      </row>
      <row>
       <entry><literal>pdo_type</literal></entry>
       <entry>The type of this column as represented by the
       <literal>PDO::PARAM_*</literal> constants.</entry>
      </row>
     </tbody>
    </tgroup>
   </table>
  <para>
   Returns &false; if the requested column does not exist in the result set,
   or if no result set exists.
  </para>
 </refsect1>

 <!-- Use when ERRORS exist
 <refsect1 role="errors">
  &reftitle.errors;
  <para>
   When does this function throw E_* level errors, or exceptions?
  </para>
 </refsect1>
 -->

 <!-- Use when a CHANGELOG exists
 <refsect1 role="changelog">
  &reftitle.changelog;
  <para>
   <informaltable>
    <tgroup cols="2">
     <thead>
      <row>
       <entry>&Version;</entry>
       <entry>&Description;</entry>
      </row>
     </thead>
     <tbody>
      <row>
       <entry>Enter the PHP version of change here
       <entry>Description of change
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1>
 -->

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title>Retrieving column metadata</title>
    <para>
     The following example shows the results of retrieving the metadata for a
     single column generated by a function (COUNT) in a PDO_SQLITE driver.
    </para>
    <programlisting role="php">
<![CDATA[
<?php
$select = $DB->query('SELECT COUNT(*) FROM fruit');
$meta = $select->getColumnMeta(0);
var_dump($meta);
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
array(6) {
  ["native_type"]=>
  string(7) "integer"
  ["flags"]=>
  array(0) {
  }
  ["name"]=>
  string(8) "COUNT(*)"
  ["len"]=>
  int(-1)
  ["precision"]=>
  int(0)
  ["pdo_type"]=>
  int(2)
}

]]>
    </screen>
   </example>
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><xref linkend="function.PDOStatement-columnCount" /></member>
    <member><xref linkend="function.PDOStatement-rowCount" /></member>
   </simplelist>
  </para>
 </refsect1>

</refentry>

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