在帖子，评论和个人资料页面上上传文件的数据库设计

I am new to web development and am trying to implement a website where users can upload photos and other files (i.e. .doc, .xls, .ppt, .txt, .pdf,etc...) on profile pages, posts and comments. I am using an s3 bucket for the file storage and will use a mysql database to store the file urls and other associative data. What I am confused about is the following: I am new to web development and am trying to im