The Seam-based applications we are developing typically handle several databases based on a common schema. When a user logs in, he/she selects one of the databases to be used for the session. In each of our application projects we have a file persistence-<profile>.xml that contains one persistence-unit for each database. The problem with this is that quite often we need to add a new database to the setup, meaning we have to build and deploy a new application (.ear) every time a new database has to be included. At the time being that may happen several times per month. Is there a smarter way to handle this? I would prefer the applications to read these persistence-unit data from an external file.