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

<?xml version="1.0" encoding="iso-8859-1"?>
<!-- splitted from ./en/functions/mysql.xml, last change in rev 1.2 -->
  <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>
    <example>
     <title><function>mysql_fetch_field</function></title>
     <programlisting role="php">
<![CDATA[
<?php
mysql_connect('localhost:3306', $user, $password)
    or die ("Could not connect");
mysql_select_db("database");
$result = mysql_query("select * from table")
    or die("Query failed");
/* get column metadata */
$i = 0;
while ($i < mysql_num_fields($result)) {
    echo "Information for column $i:<BR>\n";
    $meta = mysql_fetch_field($result);
    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>
     See also <function>mysql_field_seek</function>.
    </para>
   </refsect1>
  </refentry>

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