<!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>Models : 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</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> › Models </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>Models</h1> <p>Models are <strong>optionally</strong> available for those who want to use a more traditional MVC approach.</p> <ul> <li><a href="#what">What is a Model?</a></li> <li><a href="#anatomy">Anatomy of a Model</a></li> <li><a href="#loading">Loading a Model</a></li> <li><a href="#auto_load_model">Auto-Loading a Model</a> </li> <li><a href="#conn">Connecting to your Database</a></li> </ul> <h2><a name="what"></a>What is a Model?</h2> <p>Models are PHP classes that are designed to work with information in your database. For example, let's say you use CodeIgniter to manage a blog. You might have a model class that contains functions to insert, update, and retrieve your blog data. Here is an example of what such a model class might look like:</p> <code> class Blogmodel extends Model {<br /> <br /> var $title = '';<br /> var $content = '';<br /> var $date = '';<br /> <br /> function Blogmodel()<br /> {<br /> // Call the Model constructor<br /> parent::Model();<br /> }<br /> <br /> function get_last_ten_entries()<br /> {<br /> $query = $this->db->get('entries', 10);<br /> return $query->result();<br /> }<br /> <br /> function insert_entry()<br /> {<br /> $this->title = $_POST['title']; // please read the below note<br /> $this->content = $_POST['content'];<br /> $this->date = time();<br /> <br /> $this->db->insert('entries', $this);<br /> }<br /> <br /> function update_entry()<br /> {<br /> $this->title = $_POST['title'];<br /> $this->content = $_POST['content'];<br /> $this->date = time();<br /> <br /> $this->db->update('entries', $this, array('id' => $_POST['id']));<br /> }<br /> <br /> }</code> <p>Note: The functions in the above example use the <a href="../database/active_record.html">Active Record</a> database functions.</p> <p class="important"><strong>Note:</strong> For the sake of simplicity in this example we're using $_POST directly. This is generally bad practice, and a more common approach would be to use the <a href="../libraries/input.html">Input Class</a> $this->input->post('title')</p> <h2><a name="anatomy"></a>Anatomy of a Model</h2> <p>Model classes are stored in your <dfn>application/models/</dfn> folder. They can be nested within sub-folders if you want this type of organization.</p> <p>The basic prototype for a model class is this:</p> <code> class <var>Model_name</var> extends Model {<br /> <br /> function <var>Model_name</var>()<br /> {<br /> parent::Model();<br /> }<br /> }</code> <p>Where <var>Model_name</var> is the name of your class. Class names <strong>must</strong> have the first letter capitalized with the rest of the name lowercase. Make sure your class extends the base Model class.</p> <p>The file name will be a lower case version of your class name. For example, if your class is this:</p> <code> class <var>User_model</var> extends Model {<br /> <br /> function <var>User_model</var>()<br /> {<br /> parent::Model();<br /> }<br /> }</code> <p>Your file will be this:</p> <code>application/models/<var>user_model.php</var></code> <h2><a name="loading"></a>Loading a Model</h2> <p>Your models will typically be loaded and called from within your <a href="controllers.html">controller</a> functions. To load a model you will use the following function:</p> <code>$this->load->model('<var>Model_name</var>');</code> <p>If you model is located in a sub-folder, include the relative path from your models folder. For example, if you have a model located at <dfn>application/models/blog/queries.php</dfn> you'll load it using:</p> <code>$this->load->model('<var>blog/queries</var>');</code> <p>Once loaded, you will access your model functions using an object with the same name as your class:</p> <code> $this->load->model('<var>Model_name</var>');<br /> <br /> $this-><var>Model_name</var>->function(); </code> <p>If you would like your model assigned to a different object name you can specify it via the second parameter of the loading function:</p> <code> $this->load->model('<var>Model_name</var>', '<kbd>fubar</kbd>');<br /> <br /> $this-><kbd>fubar</kbd>->function(); </code> <p>Here is an example of a controller, that loads a model, then serves a view:</p> <code> class Blog_controller extends Controller {<br /> <br /> function blog()<br /> {<br /> $this->load->model('Blog');<br /> <br /> $data['query'] = $this->Blog->get_last_ten_entries();<br /><br /> $this->load->view('blog', $data);<br /> }<br /> }</code> <h2><a name="auto_load_model" id="auto_load_model"></a>Auto-loading Models</h2> <p>If you find that you need a particular model globally throughout your application, you can tell CodeIgniter to auto-load it during system initialization. This is done by opening the application/config/autoload.php file and adding the model to the autoload array.</p> <h2><a name="conn"></a>Connecting to your Database</h2> <p>When a model is loaded it does <strong>NOT</strong> connect automatically to your database. The following options for connecting are available to you:</p> <ul> <li>You can connect using the standard database methods <a href="../database/connecting.html">described here</a>, either from within your Controller class or your Model class.</li> <li>You can tell the model loading function to auto-connect by passing <kbd>TRUE</kbd> (boolean) via the third parameter, and connectivity settings, as defined in your database config file will be used: <code>$this->load->model('<var>Model_name</var>', '', <kbd>TRUE</kbd>);</code> </li> <li>You can manually pass database connectivity settings via the third parameter: <code>$config['hostname'] = "localhost";<br /> $config['username'] = "myusername";<br /> $config['password'] = "mypassword";<br /> $config['database'] = "mydatabase";<br /> $config['dbdriver'] = "mysql";<br /> $config['dbprefix'] = "";<br /> $config['pconnect'] = FALSE;<br /> $config['db_debug'] = TRUE;<br /> <br /> $this->load->model('<var>Model_name</var>', '', <kbd>$config</kbd>);</code></li> </ul> </div> <!-- END CONTENT --> <div id="footer"> <p> Previous Topic: <a href="views.html">Views</a> · <a href="#top">Top of Page</a> · <a href="../index.html">User Guide Home</a> · Next Topic: <a href="helpers.html">Helpers</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>