I went through this tutorial: http://www.smashingmagazine.com/2014/03/13/tutorial-create-admin-manageable-magento-entity-brands/.
When accessing the post data, the author uses:
$this->getRequest()->getPost('brandData')
I am wondering how can we know there is a brandData key in the post data?
NOTE: I know I can see the available keys using the
var_dump($this->getRequest()->getPost())
But I want to know how to know it without manually print the whole post data.