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| Derek Jones | 733310d | 2009-02-11 01:13:43 +0000 | [diff] [blame] | 30 | <td><h1>CodeIgniter User Guide Version 1.7.1</h1></td> |
| Derek Allard | 2067d1a | 2008-11-13 22:59:24 +0000 | [diff] [blame] | 31 | <td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td> |
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| 42 | <a href="http://codeigniter.com/">CodeIgniter Home</a> › |
| 43 | <a href="../index.html">User Guide Home</a> › |
| 44 | Models |
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| 55 | <div id="content"> |
| 56 | |
| 57 | <h1>Models</h1> |
| 58 | |
| 59 | <p>Models are <strong>optionally</strong> available for those who want to use a more traditional MVC approach.</p> |
| 60 | |
| 61 | |
| 62 | |
| 63 | <ul> |
| 64 | <li><a href="#what">What is a Model?</a></li> |
| 65 | <li><a href="#anatomy">Anatomy of a Model</a></li> |
| 66 | <li><a href="#loading">Loading a Model</a></li> |
| 67 | <li><a href="#auto_load_model">Auto-Loading a Model</a> </li> |
| 68 | <li><a href="#conn">Connecting to your Database</a></li> |
| 69 | </ul> |
| 70 | |
| 71 | |
| 72 | |
| 73 | <h2><a name="what"></a>What is a Model?</h2> |
| 74 | |
| 75 | <p>Models are PHP classes that are designed to work with information in your database. For example, let's say |
| 76 | you use CodeIgniter to manage a blog. You might have a model class that contains functions to insert, update, and |
| 77 | retrieve your blog data. Here is an example of what such a model class might look like:</p> |
| 78 | |
| 79 | <code> |
| 80 | class Blogmodel extends Model {<br /> |
| 81 | <br /> |
| 82 | var $title = '';<br /> |
| 83 | var $content = '';<br /> |
| 84 | var $date = '';<br /> |
| 85 | <br /> |
| 86 | function Blogmodel()<br /> |
| 87 | {<br /> |
| 88 | // Call the Model constructor<br /> |
| 89 | parent::Model();<br /> |
| 90 | }<br /> |
| 91 | <br /> |
| 92 | function get_last_ten_entries()<br /> |
| 93 | {<br /> |
| 94 | $query = $this->db->get('entries', 10);<br /> |
| 95 | return $query->result();<br /> |
| 96 | }<br /> |
| 97 | <br /> |
| 98 | function insert_entry()<br /> |
| 99 | {<br /> |
| 100 | $this->title = $_POST['title']; // please read the below note<br /> |
| 101 | $this->content = $_POST['content'];<br /> |
| 102 | $this->date = time();<br /> |
| 103 | <br /> |
| 104 | $this->db->insert('entries', $this);<br /> |
| 105 | }<br /> |
| 106 | <br /> |
| 107 | function update_entry()<br /> |
| 108 | {<br /> |
| 109 | $this->title = $_POST['title'];<br /> |
| 110 | $this->content = $_POST['content'];<br /> |
| 111 | $this->date = time();<br /> |
| 112 | <br /> |
| 113 | $this->db->update('entries', $this, array('id' => $_POST['id']));<br /> |
| 114 | }<br /> |
| 115 | <br /> |
| 116 | }</code> |
| 117 | |
| 118 | <p>Note: The functions in the above example use the <a href="../database/active_record.html">Active Record</a> database functions.</p> |
| 119 | <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> $this->input->post('title')</p> |
| 120 | <h2><a name="anatomy"></a>Anatomy of a Model</h2> |
| 121 | |
| 122 | <p>Model classes are stored in your <dfn>application/models/</dfn> folder. They can be nested within sub-folders if you |
| 123 | want this type of organization.</p> |
| 124 | |
| 125 | <p>The basic prototype for a model class is this:</p> |
| 126 | |
| 127 | |
| 128 | <code> |
| 129 | class <var>Model_name</var> extends Model {<br /> |
| 130 | <br /> |
| 131 | function <var>Model_name</var>()<br /> |
| 132 | {<br /> |
| 133 | parent::Model();<br /> |
| 134 | }<br /> |
| 135 | }</code> |
| 136 | |
| 137 | <p>Where <var>Model_name</var> is the name of your class. Class names <strong>must</strong> have the first letter capitalized with the rest of the name lowercase. |
| 138 | Make sure your class extends the base Model class.</p> |
| 139 | |
| 140 | <p>The file name will be a lower case version of your class name. For example, if your class is this:</p> |
| 141 | |
| 142 | <code> |
| 143 | class <var>User_model</var> extends Model {<br /> |
| 144 | <br /> |
| 145 | function <var>User_model</var>()<br /> |
| 146 | {<br /> |
| 147 | parent::Model();<br /> |
| 148 | }<br /> |
| 149 | }</code> |
| 150 | |
| 151 | <p>Your file will be this:</p> |
| 152 | |
| 153 | <code>application/models/<var>user_model.php</var></code> |
| 154 | |
| 155 | |
| 156 | |
| 157 | <h2><a name="loading"></a>Loading a Model</h2> |
| 158 | |
| 159 | <p>Your models will typically be loaded and called from within your <a href="controllers.html">controller</a> functions. |
| 160 | To load a model you will use the following function:</p> |
| 161 | |
| 162 | <code>$this->load->model('<var>Model_name</var>');</code> |
| 163 | |
| 164 | <p>If you model is located in a sub-folder, include the relative path from your models folder. For example, if |
| 165 | you have a model located at <dfn>application/models/blog/queries.php</dfn> you'll load it using:</p> |
| 166 | |
| 167 | <code>$this->load->model('<var>blog/queries</var>');</code> |
| 168 | |
| 169 | |
| 170 | <p>Once loaded, you will access your model functions using an object with the same name as your class:</p> |
| 171 | |
| 172 | <code> |
| 173 | $this->load->model('<var>Model_name</var>');<br /> |
| 174 | <br /> |
| 175 | $this-><var>Model_name</var>->function(); |
| 176 | </code> |
| 177 | |
| 178 | <p>If you would like your model assigned to a different object name you can specify it via the second parameter of the loading |
| 179 | function:</p> |
| 180 | |
| 181 | |
| 182 | <code> |
| 183 | $this->load->model('<var>Model_name</var>', '<kbd>fubar</kbd>');<br /> |
| 184 | <br /> |
| 185 | $this-><kbd>fubar</kbd>->function(); |
| 186 | </code> |
| 187 | |
| 188 | <p>Here is an example of a controller, that loads a model, then serves a view:</p> |
| 189 | |
| 190 | <code> |
| 191 | class Blog_controller extends Controller {<br /> |
| 192 | <br /> |
| 193 | function blog()<br /> |
| 194 | {<br /> |
| 195 | $this->load->model('Blog');<br /> |
| 196 | <br /> |
| 197 | $data['query'] = $this->Blog->get_last_ten_entries();<br /><br /> |
| 198 | $this->load->view('blog', $data);<br /> |
| 199 | }<br /> |
| 200 | }</code> |
| 201 | |
| 202 | <h2><a name="auto_load_model" id="auto_load_model"></a>Auto-loading Models</h2> |
| 203 | <p>If you find that you need a particular model globally throughout your application, you can tell CodeIgniter to auto-load it during system initialization. This is done by opening the application/config/autoload.php file and adding the model to the autoload array.</p> |
| 204 | |
| 205 | |
| 206 | <h2><a name="conn"></a>Connecting to your Database</h2> |
| 207 | |
| 208 | <p>When a model is loaded it does <strong>NOT</strong> connect automatically to your database. The following options for connecting are available to you:</p> |
| 209 | |
| 210 | <ul> |
| 211 | <li>You can connect using the standard database methods <a href="../database/connecting.html">described here</a>, either from within your Controller class or your Model class.</li> |
| 212 | <li>You can tell the model loading function to auto-connect by passing <kbd>TRUE</kbd> (boolean) via the third parameter, |
| 213 | and connectivity settings, as defined in your database config file will be used: |
| 214 | |
| 215 | <code>$this->load->model('<var>Model_name</var>', '', <kbd>TRUE</kbd>);</code> |
| 216 | </li> |
| 217 | |
| 218 | |
| 219 | <li>You can manually pass database connectivity settings via the third parameter: |
| 220 | |
| 221 | |
| 222 | <code>$config['hostname'] = "localhost";<br /> |
| 223 | $config['username'] = "myusername";<br /> |
| 224 | $config['password'] = "mypassword";<br /> |
| 225 | $config['database'] = "mydatabase";<br /> |
| 226 | $config['dbdriver'] = "mysql";<br /> |
| 227 | $config['dbprefix'] = "";<br /> |
| 228 | $config['pconnect'] = FALSE;<br /> |
| 229 | $config['db_debug'] = TRUE;<br /> |
| 230 | <br /> |
| 231 | $this->load->model('<var>Model_name</var>', '', <kbd>$config</kbd>);</code></li> |
| 232 | </ul> |
| 233 | |
| 234 | |
| 235 | </div> |
| 236 | <!-- END CONTENT --> |
| 237 | |
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| admin | b0dd10f | 2006-08-25 17:25:49 +0000 | [diff] [blame] | 251 | </html> |