The queries are translated into operation over views. When relational databases are used, these views will be effciently compilable. Other files can only support a single view. Conventional mediator technology can be used or invoked to deal with heterogeneous resources within a domain. The security mediator may also keep passwords to domain resources in encrypted form.
Decryption requires a password to be submitted by an authenticated customer.
Keeping domain password within the mediator avoids their dissemination into environments that are not secure, and permits selected denial of access to customers when their authority changes. Note that even an empty, rule-less, security mediator can greatly improve operations. Without rules all interactions are presented to the security officer, but they are now viewed on-line, and immediatly editable, if needed. In time simple rules can be entered to reduces the load on the officer. Coverage of Access Paths .