title: CDbConnection.connectionString cannot be empty
body: <p>I working with yii framework now. created one project name -"yii".
  In that project i have demo folder in which one another first </p>
  
  <pre><code>                         yii/demo/first
  </code></pre>
  
  <p>In that folder i had created </p>
  
  <pre><code>yii/demo/first/
                -&gt;protected-&gt;config-&gt;main.php
                -&gt;controller-&gt;SiteController.php
                -&gt;view-&gt;site-&gt;view.php
  </code></pre>
  
  <p>I am also placing one <strong>screen shot</strong> to show above..</p>
  
  <p>In main file i had placed connection string as shown in screenshot</p>
  
  <p><a href="https://i.stack.imgur.com/5AC8I.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5AC8I.png" alt="enter image description here"></a></p>
  
  <p>I had also created database name as "student" in mysql</p>
  
  <p>still when i run this site i get error like </p>
  
  <p><a href="https://i.stack.imgur.com/OdanU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/OdanU.png" alt="enter image description here"></a></p>
  
  <p><strong>I had placed connection string still showing that error.</strong></p>
  
  <p>If any mistake in above code that please tell me..   </p>