It kind of does have to be one file, because foreign keys can't be enforced across files.
For a simple example, if you have one db file per user, as others recommend, how do you check that a username or an email is unique? Do you maintain a "global" db for fields with unique constraints? But then when those fields are updated you need to manage this at the application level, and atomicity can't really be guaranteed... Or is there another way?
For a simple example, if you have one db file per user, as others recommend, how do you check that a username or an email is unique? Do you maintain a "global" db for fields with unique constraints? But then when those fields are updated you need to manage this at the application level, and atomicity can't really be guaranteed... Or is there another way?