your post doesn't make a lott of sense to me.
what you normally do is store the file in some directory, and then you only store the path to the file inside your db.
if you then want to show all the files that were generated for that user, then you just run a select on your table, and you display a link to each file (using the path from the db inside the link-tag).
so when you create the pdf on your server, you give it some unique name, like username_date_time.pdf, and then you store the path in your db. if you only want to keep 1 file for each user, then just always name the file like username.pdf.
if you upload the file from the users local, then you rename the file and move it from the temporarely directory to wherevere you want to store the files, and then again store the path in your db.