php-doc-en/reference/mysql/functions/mysql-fetch-field.xml

<?xml version="1.0" encoding="iso-8859-1"?>
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<refentry id="function.mysql-fetch-field">
 <refnamediv>
  <refname>mysql_fetch_field</refname>
  <refpurpose>
   Get column information from a result and return as an object
  </refpurpose>
 </refnamediv>
 <refsect1>
  <title>Description</title>
   <methodsynopsis>
    <type>object</type><methodname>mysql_fetch_field</methodname>
    <methodparam><type>resource</type><parameter>result</parameter></methodparam>
    <methodparam choice="opt"><type>int</type><parameter>
      field_offset
     </parameter></methodparam>
   </methodsynopsis>
  <para>
   Returns an object containing field information.
  </para>
  <para>
   <function>mysql_fetch_field</function> can be used in order to
   obtain information about fields in a certain query result.  If
   the field offset isn't specified, the next field that wasn't yet
   retrieved by <function>mysql_fetch_field</function> is retrieved.
  </para>
  <para>
   The properties of the object are:
   <itemizedlist>
    <listitem>
     <simpara>
      name - column name
     </simpara>
    </listitem>
    <listitem>
     <simpara>
      table - name of the table the column belongs to
     </simpara>
    </listitem>
    <listitem>
     <simpara>
      max_length - maximum length of the column
     </simpara>
    </listitem>
    <listitem>
     <simpara>
      not_null - 1 if the column cannot be &null;
     </simpara>
    </listitem>
    <listitem>
     <simpara>
      primary_key - 1 if the column is a primary key
     </simpara>
    </listitem>
    <listitem>
     <simpara>
      unique_key - 1 if the column is a unique key
     </simpara>
    </listitem>
    <listitem>
     <simpara>
      multiple_key - 1 if the column is a non-unique key
     </simpara>
    </listitem>
    <listitem>
     <simpara>
      numeric - 1 if the column is numeric
     </simpara>
    </listitem>
    <listitem>
     <simpara>
      blob - 1 if the column is a BLOB
     </simpara>
    </listitem>
    <listitem>
     <simpara>
      type - the type of the column
     </simpara>
    </listitem>
    <listitem>
     <simpara>
      unsigned - 1 if the column is unsigned
     </simpara>
    </listitem>
    <listitem>
     <simpara>
      zerofill - 1 if the column is zero-filled
     </simpara>
    </listitem>
   </itemizedlist>
  </para>
  &database.field-case;
  <para>
   <example>
    <title><function>mysql_fetch_field</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
$conn = mysql_connect('localhost:3306', 'user', 'password');
if (!$conn) {
    die('Could not connect: ' . mysql_error());
}
mysql_select_db('database');
$result = mysql_query('select * from table');
if (!$result) {
    die('Query failed: ' . mysql_error());
}
/* get column metadata */
$i = 0;
while ($i < mysql_num_fields($result)) {
    echo "Information for column $i:<br />\n";
    $meta = mysql_fetch_field($result, $i);
    if (!$meta) {
        echo "No information available<br />\n";
    }
    echo "<pre>
blob:         $meta->blob
max_length:   $meta->max_length
multiple_key: $meta->multiple_key
name:         $meta->name
not_null:     $meta->not_null
numeric:      $meta->numeric
primary_key:  $meta->primary_key
table:        $meta->table
type:         $meta->type
unique_key:   $meta->unique_key
unsigned:     $meta->unsigned
zerofill:     $meta->zerofill
</pre>";
    $i++;
}
mysql_free_result($result);
?>
]]>
    </programlisting>
   </example>
  </para>
  <para>
   See also <function>mysql_field_seek</function>.
  </para>
 </refsect1>
</refentry>

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