I am new to Yii and overall love the approach of the code generator for the whole MVC stack. However, I have a pretty basic requirement; I have a form that has an optional field ‘price’ into which the user can optionally enter a number. If the user enters nothing into that form field activeRecord tries to insert an empty string into an float field and the whole thing blows up. I imagine there must be a really easy way (maybe through model rules) to only insert/update a field if the user has entered something that passes validation.