title: Yii params condition ( PHP Framework )
body: <p>I am a complete newbie in the world of yii and doing my best to learn the framework as best as I can, while reading the book on Yii - '<strong>Web Application Development Using Yii and PHP</strong>' by <em>Jeffrey Winesett</em>,</p>
  
  <p>I came across :</p>
  
  <pre><code>'params'=&gt;array(':projectId'=&gt;$this-&gt;_project-&gt;id)
  </code></pre>
  
  <p>If anyone has read the book, can someone explain why do we use <em>:projectId</em> why not directly <em>projectId</em>? <strong>What does the ':' stand for?</strong> Is it the specific syntax or is it something php specific.</p>
  
  <p>This was the exact code :</p>
  
  <pre><code>public function actionIndex()
      {
  
          $dataProvider=new CActiveDataProvider('Issue', array(
              'criteria'=&gt;array(
                  'condition'=&gt;'project_id=:projectId',
                  'params'=&gt;array(':projectId'=&gt;$this-&gt;_project-&gt;id),
              ),
          ));
          $this-&gt;render('index',array(
              'dataProvider'=&gt;$dataProvider,
          ));
      }
  </code></pre>
  
  <p>Any answer would be highly appreciated.
  Regards. </p>