How to upload a file URL to the postgres database using process variables. Also how to call that uploaded file in a form again to download it

I have prepared a form using the process variable. Now I have to attach a file from the user, This File must be uploaded on the database and another user will download it from another form. So how to upload files to the database and call them for downloading

upload and download file to BDM Database

Hello, does anybody here know how to upload excel file and download excel file to bdm database? previously i created similar question here https://community.bonitasoft.com/node/33108#node-33131, but the sample given wasn't suit to my project. So let me explain a bit what my project need. In my Project there is a features called upload and download excel file to or from BDM database. Upload and download is a seperate process.