<?php
class AccountsDbConnection extends CDbConnection
{
	public $host;

	public $type;

	public $baseName;

	public $keys = array(
		'user' => null,
		'pass' => null,
		'db'   => null,
	);


	public function init()
	{
		$this->username = $this->getKey('user');
		$this->password = $this->getKey('pass');
		$db = $this->getKey('db');

		$this->connectionString = strtr('{type}:host={host};dbname={baseName}{db}', array(
		 '{type}' => $this->type,
		 '{host}' => $this->host,
		 '{baseName}' => $this->baseName,
		 '{db}' => $db,
		));

		return parent::init();
	}

	protected function getKey($index)
	{
		// ... return value stored in session
	}

}