163 lines
5.2 KiB
HTML
163 lines
5.2 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<title>Field Data : CodeIgniter User Guide</title>
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<meta name='author' content='ExpressionEngine Dev Team' />
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<meta name='description' content='CodeIgniter User Guide' />
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<div id="nav"><div id="nav_inner"><script type="text/javascript">create_menu('../');</script></div></div>
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<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>
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<div id="masthead">
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<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
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<tr>
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<td><h1>CodeIgniter User Guide Version 1.7.3</h1></td>
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<td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td>
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</tr>
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</table>
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<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
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<tr>
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<td id="breadcrumb">
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<a href="http://codeigniter.com/">CodeIgniter Home</a> ›
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<a href="../index.html">User Guide Home</a> ›
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<a href="index.html">Database Library</a> ›
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Field Names
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</td>
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<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>
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</table>
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<br clear="all" />
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<!-- START CONTENT -->
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<div id="content">
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<h1>Field Data</h1>
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<h2>$this->db->list_fields()</h2>
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<p>Returns an array containing the field names. This query can be called two ways:</p>
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<p>1. You can supply the table name and call it from the <dfn>$this->db-></dfn> object:</p>
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<code>
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$fields = $this->db->list_fields('table_name');<br /><br />
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foreach ($fields as $field)<br />
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{<br />
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echo $field;<br />
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}
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</code>
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<p>2. You can gather the field names associated with any query you run by calling the function
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from your query result object:</p>
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<code>
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$query = $this->db->query('SELECT * FROM some_table');
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<br /><br />
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foreach ($query->list_fields() as $field)<br />
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{<br />
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echo $field;<br />
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}
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</code>
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<h2>$this->db->field_exists()</h2>
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<p>Sometimes it's helpful to know whether a particular field exists before performing an action.
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Returns a boolean TRUE/FALSE. Usage example:</p>
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<code>
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if ($this->db->field_exists('field_name', 'table_name'))<br />
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{<br />
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// some code...<br />
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}
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</code>
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<p>Note: Replace <em>field_name</em> with the name of the column you are looking for, and replace
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<em>table_name</em> with the name of the table you are looking for.</p>
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<h2>$this->db->field_data()</h2>
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<p>Returns an array of objects containing field information.</p>
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<p>Sometimes it's helpful to gather the field names or other metadata, like the column type, max length, etc.</p>
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<p class="important">Note: Not all databases provide meta-data.</p>
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<p>Usage example:</p>
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<code>
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$fields = $this->db->field_data('table_name');<br /><br />
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foreach ($fields as $field)<br />
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{<br />
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echo $field->name;<br />
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echo $field->type;<br />
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echo $field->max_length;<br />
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echo $field->primary_key;<br />
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}
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</code>
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<p>If you have run a query already you can use the result object instead of supplying the table name:</p>
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<code>
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$query = $this->db->query("YOUR QUERY");<br />
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$fields = $query->field_data();
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</code>
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<p>The following data is available from this function if supported by your database:</p>
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<ul>
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<li>name - column name</li>
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<li>max_length - maximum length of the column</li>
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<li>primary_key - 1 if the column is a primary key</li>
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<li>type - the type of the column</li>
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</ul>
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</div>
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<!-- END CONTENT -->
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<div id="footer">
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<p>
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Previous Topic: <a href="table_data.html"> Table Data</a>
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·
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<a href="#top">Top of Page</a> ·
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<a href="../index.html">User Guide Home</a> ·
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Next Topic: <a href="call_function.html">Custom Function Calls</a>
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</p>
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