How can MySQL return an empty row matching a given table's schema, given the table name as an input string?

How can a query or procedure return an empty copy of a new record? Ideally suited for objects which are in a transactional allocation process: It is highly preferable to have authoritative defaults and NULLS for arbitrary tables when constructing new objects() that *may-or-may not* ultimately be saved to the database. For example, a CMS user relies on AJAX which calls for a new post() or new product() dynamically. Rather than trusting stored profiles to set values in the scripting language, a blank "instance" of a row would be rather useful.