Tabular data Managing in PHP


I’m making a (non-flash) XHTML strict/CSS website and my “client” needs to have a page where he can update some data in tables. It’s only that one page in the whole website that needs to be updated. Can anyone recommend a secure PHP script that generates this page and can be updated. I searched for hours but can only find complex CMS or invalid html. I know some basic php and mysql but not enough to make it myself.