A database model document maintains meta-data behind the diagram. This allows Visio to check the model for errors, generate ...

A database model document maintains meta-data behind the diagram.  This allows Visio to check the model for errors, generate a physical database, or reverse engineer an existing database.  A database model document can also be used as a "project" document in which its logical schema will be the result of merging one or more (ER and/or ORM) Source Model documents .