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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>Field Data : CodeIgniter User Guide</title><style type='text/css' media='all'>@import url('../userguide.css');</style><link rel='stylesheet' type='text/css' media='all' href='../userguide.css' /><script type="text/javascript" src="../nav/nav.js"></script><script type="text/javascript" src="../nav/prototype.lite.js"></script><script type="text/javascript" src="../nav/moo.fx.js"></script><script type="text/javascript" src="../nav/user_guide_menu.js"></script><meta http-equiv='expires' content='-1' /><meta http-equiv= 'pragma' content='no-cache' /><meta name='robots' content='all' /><meta name='author' content='ExpressionEngine Dev Team' /><meta name='description' content='CodeIgniter User Guide' /></head><body><!-- START NAVIGATION --><div id="nav"><div id="nav_inner"><script type="text/javascript">create_menu('../');</script></div></div><div id="nav2"><a name="top"></a><a href="javascript:void(0);" onclick="myHeight.toggle();"><img src="../images/nav_toggle_darker.jpg" width="154" height="43" border="0" title="Toggle Table of Contents" alt="Toggle Table of Contents" /></a></div><div id="masthead"><table cellpadding="0" cellspacing="0" border="0" style="width:100%"><tr><td><h1>CodeIgniter User Guide Version 1.7.1</h1></td><td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td></tr></table></div><!-- END NAVIGATION --><!-- START BREADCRUMB --><table cellpadding="0" cellspacing="0" border="0" style="width:100%"><tr><td id="breadcrumb"><a href="http://codeigniter.com/">CodeIgniter Home</a> › <a href="../index.html">User Guide Home</a> › <a href="index.html">Database Library</a> › Field Names</td><td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="codeigniter.com/user_guide/" />Search User Guide <input type="text" class="input" style="width:200px;" name="q" id="q" size="31" maxlength="255" value="" /> <input type="submit" class="submit" name="sa" value="Go" /></form></td></tr></table><!-- END BREADCRUMB --><br clear="all" /><!-- START CONTENT --><div id="content"><h1>Field Data</h1><h2>$this->db->list_fields()</h2><p>Returns an array containing the field names. This query can be called two ways:</p><p>1. You can supply the table name and call it from the <dfn>$this->db-></dfn> object:</p><code>$fields = $this->db->list_fields('table_name');<br /><br />foreach ($fields as $field)<br />{<br /> echo $field;<br />}</code><p>2. You can gather the field names associated with any query you run by calling the functionfrom your query result object:</p><code>$query = $this->db->query('SELECT * FROM some_table');<br /><br />foreach ($query->list_fields() as $field)<br />{<br /> echo $field;<br />}</code><h2>$this->db->field_exists()</h2><p>Sometimes it's helpful to know whether a particular field exists before performing an action.Returns a boolean TRUE/FALSE. Usage example:</p><code>if ($this->db->field_exists('field_name', 'table_name'))<br />{<br /> // some code...<br />}</code><p>Note: Replace <em>field_name</em> with the name of the column you are looking for, and replace<em>table_name</em> with the name of the table you are looking for.</p><h2>$this->db->field_data()</h2><p>Returns an array of objects containing field information.</p><p>Sometimes it's helpful to gather the field names or other metadata, like the column type, max length, etc.</p><p class="important">Note: Not all databases provide meta-data.</p><p>Usage example:</p><code>$fields = $this->db->field_data('table_name');<br /><br />foreach ($fields as $field)<br />{<br /> echo $field->name;<br /> echo $field->type;<br /> echo $field->max_length;<br /> echo $field->primary_key;<br />}</code><p>If you have run a query already you can use the result object instead of supplying the table name:</p><code>$query = $this->db->query("YOUR QUERY");<br />$fields = $query->field_data();</code><p>The following data is available from this function if supported by your database:</p><ul><li>name - column name</li><li>max_length - maximum length of the column</li><li>primary_key - 1 if the column is a primary key</li><li>type - the type of the column</li></ul></div><!-- END CONTENT --><div id="footer"><p>Previous Topic: <a href="table_data.html"> Table Data</a> · <a href="#top">Top of Page</a> · <a href="../index.html">User Guide Home</a> · Next Topic: <a href="call_function.html">Custom Function Calls</a></p><p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006-2008 · <a href="http://ellislab.com/">Ellislab, Inc.</a></p></div></body></html>