Helper Script To Automatically Split 7z/Zip Files On Server Then Update DB

I have many 7z files above 3.5GBs that need to be split into (3) smaller files (~33.333% each). After they are split on the server, I want to update the 'filepath' columns in the database, and add another column for 'file_amount' so the site will know if there are multiple files available. Open for ideas. My server admin says I have 7za installed on my centos server that can do this. So I need a script that automatically splits all files about 3.5GB and updates database.