I\'m creating a website using MVC framework (Yii) and I need to dynamically create subdomains, i.e. http://company.website.com
So, in order to achieve this
If I understand your question, the 'company' component of the URL is a variable company name. I'll continue my answer under that assumption.
Another option would be to create a company module (I'll call it 'Companies' for now), and use the CUrlManager rules to route to that controller. E.g.
array(
'http://.website.com/user/register' => '/companies/user/register',
'http://.website.com/<_c:\w+>/<_a:\w+>' => '/companies/<_c>/<_a>' // more generic option
),
The 'company' string will be passed to the application as $_GET['company'] and you can use this parameter in your CompaniesModule.php file to load some company specific data.
Please note that without some other rule to handle www.website.com requests (as per Grey Teardrop's answer) you will get errors on requests to that subdomain.