I'm building an application that will store sensitive data for several large customer companies. We want the customers to be able to login and see reporting/dashboards related to their info, but obviously not see the sensitive information of the other companies. 

The information will be uploaded by our team, and not by the customers themselves. Is there a way to associate customers to only their related data, so when they access the portal they only see their information? Is it secure to have multiple clients accessing the same database like this?

Otherwise, would it be wiser to simply duplicate the application for each client, and host their data separately?

Thanks!

Brian