251 lines
10 KiB
HTML
251 lines
10 KiB
HTML
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<!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>Models : CodeIgniter User Guide</title>
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<style type='text/css' media='all'>@import url('../userguide.css');</style>
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<link rel='stylesheet' type='text/css' media='all' href='../userguide.css' />
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<script type="text/javascript" src="../nav/nav.js"></script>
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<script type="text/javascript" src="../nav/prototype.lite.js"></script>
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<script type="text/javascript" src="../nav/moo.fx.js"></script>
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<script type="text/javascript" src="../nav/user_guide_menu.js"></script>
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<meta http-equiv='expires' content='-1' />
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<meta http-equiv= 'pragma' content='no-cache' />
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<meta name='robots' content='all' />
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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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</head>
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<body>
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<!-- START NAVIGATION -->
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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 2.1.3</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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</div>
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<!-- END NAVIGATION -->
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<!-- START BREADCRUMB -->
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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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Models
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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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</tr>
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</table>
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<!-- END BREADCRUMB -->
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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>Models</h1>
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<p>Models are <strong>optionally</strong> available for those who want to use a more traditional MVC approach.</p>
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<ul>
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<li><a href="#what">What is a Model?</a></li>
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<li><a href="#anatomy">Anatomy of a Model</a></li>
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<li><a href="#loading">Loading a Model</a></li>
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<li><a href="#auto_load_model">Auto-Loading a Model</a> </li>
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<li><a href="#conn">Connecting to your Database</a></li>
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</ul>
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<h2><a name="what"></a>What is a Model?</h2>
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<p>Models are PHP classes that are designed to work with information in your database. For example, let's say
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you use CodeIgniter to manage a blog. You might have a model class that contains functions to insert, update, and
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retrieve your blog data. Here is an example of what such a model class might look like:</p>
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<code>
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class Blogmodel extends CI_Model {<br />
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<br />
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var $title = '';<br />
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var $content = '';<br />
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var $date = '';<br />
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<br />
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function __construct()<br />
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{<br />
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// Call the Model constructor<br />
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parent::__construct();<br />
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}<br />
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<br />
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function get_last_ten_entries()<br />
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{<br />
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$query = $this->db->get('entries', 10);<br />
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return $query->result();<br />
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}<br />
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<br />
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function insert_entry()<br />
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{<br />
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$this->title = $_POST['title']; // please read the below note<br />
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$this->content = $_POST['content'];<br />
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$this->date = time();<br />
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<br />
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$this->db->insert('entries', $this);<br />
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}<br />
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<br />
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function update_entry()<br />
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{<br />
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$this->title = $_POST['title'];<br />
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$this->content = $_POST['content'];<br />
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$this->date = time();<br />
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<br />
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$this->db->update('entries', $this, array('id' => $_POST['id']));<br />
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}<br />
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<br />
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}</code>
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<p>Note: The functions in the above example use the <a href="../database/active_record.html">Active Record</a> database functions.</p>
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<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>
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<h2><a name="anatomy"></a>Anatomy of a Model</h2>
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<p>Model classes are stored in your <dfn>application/models/</dfn> folder. They can be nested within sub-folders if you
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want this type of organization.</p>
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<p>The basic prototype for a model class is this:</p>
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<code>
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class <var>Model_name</var> extends CI_Model {<br />
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<br />
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function <var>__construct</var>()<br />
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{<br />
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parent::__construct();<br />
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}<br />
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}</code>
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<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.
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Make sure your class extends the base Model class.</p>
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<p>The file name will be a lower case version of your class name. For example, if your class is this:</p>
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<code>
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class <var>User_model</var> extends CI_Model {<br />
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<br />
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function <var>__construct</var>()<br />
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{<br />
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parent::__construct();<br />
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}<br />
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}</code>
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<p>Your file will be this:</p>
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<code>application/models/<var>user_model.php</var></code>
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<h2><a name="loading"></a>Loading a Model</h2>
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<p>Your models will typically be loaded and called from within your <a href="controllers.html">controller</a> functions.
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To load a model you will use the following function:</p>
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<code>$this->load->model('<var>Model_name</var>');</code>
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<p>If your model is located in a sub-folder, include the relative path from your models folder. For example, if
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you have a model located at <dfn>application/models/blog/queries.php</dfn> you'll load it using:</p>
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<code>$this->load->model('<var>blog/queries</var>');</code>
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<p>Once loaded, you will access your model functions using an object with the same name as your class:</p>
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<code>
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$this->load->model('<var>Model_name</var>');<br />
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<br />
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$this-><var>Model_name</var>->function();
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</code>
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<p>If you would like your model assigned to a different object name you can specify it via the second parameter of the loading
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function:</p>
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<code>
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$this->load->model('<var>Model_name</var>', '<kbd>fubar</kbd>');<br />
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<br />
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$this-><kbd>fubar</kbd>->function();
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</code>
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<p>Here is an example of a controller, that loads a model, then serves a view:</p>
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<code>
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class Blog_controller extends CI_Controller {<br />
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<br />
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function blog()<br />
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{<br />
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$this->load->model('Blog');<br />
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<br />
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$data['query'] = $this->Blog->get_last_ten_entries();<br /><br />
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$this->load->view('blog', $data);<br />
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}<br />
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}</code>
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<h2><a name="auto_load_model" id="auto_load_model"></a>Auto-loading Models</h2>
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<p>If you find that you need a particular model globally throughout your application, you can tell CodeIgniter to auto-load it during system initialization. This is done by opening the application/config/autoload.php file and adding the model to the autoload array.</p>
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<h2><a name="conn"></a>Connecting to your Database</h2>
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<p>When a model is loaded it does <strong>NOT</strong> connect automatically to your database. The following options for connecting are available to you:</p>
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<ul>
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<li>You can connect using the standard database methods <a href="../database/connecting.html">described here</a>, either from within your Controller class or your Model class.</li>
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<li>You can tell the model loading function to auto-connect by passing <kbd>TRUE</kbd> (boolean) via the third parameter,
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and connectivity settings, as defined in your database config file will be used:
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<code>$this->load->model('<var>Model_name</var>', '', <kbd>TRUE</kbd>);</code>
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</li>
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<li>You can manually pass database connectivity settings via the third parameter:
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<code>$config['hostname'] = "localhost";<br />
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$config['username'] = "myusername";<br />
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$config['password'] = "mypassword";<br />
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$config['database'] = "mydatabase";<br />
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$config['dbdriver'] = "mysql";<br />
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$config['dbprefix'] = "";<br />
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$config['pconnect'] = FALSE;<br />
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$config['db_debug'] = TRUE;<br />
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<br />
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$this->load->model('<var>Model_name</var>', '', <kbd>$config</kbd>);</code></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="views.html">Views</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="helpers.html">Helpers</a>
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</p>
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<p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006 - 2012 · <a href="http://ellislab.com/">EllisLab, Inc.</a></p>
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</div>
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</body>
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</html>
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