Making changes to databases in phpmyadmin but they are not reflecting on my site

Hi there, My site allows users to input certain contact information into a database. One of the fields is currently market as "required" but I wanted to change it. I went into phpmyadmin and updated the field to be "null" but the changes are not reflecting on the live site. Is there something I also need to do inside cpanel file manager to make sure the changes happened or configuring something together?