INFS614 George Mason University
An Example for ER Modeling
Assume the university computing services (UCS) administers all campus computer
networks. Each computer in a network is uniquely identifed by an inventory
number, and also has a name (e.g., ise.gmu.edu) and a model (e.g., Dell Laptop).
Computers are connected via networks. Each network has an identification number
(id) and a capacity. Each computer is connected to a single network. The number of
computers that are connected to a network may not exceed the capacity of the
network. Each computer can have several peripheral devices. Each peripheral is
installed in a specific io-port (e.g., USB slot #1); io-port numbers are unique within
the computer, and has device name for the device currently associated with it (e.g,
external disk drive). Users are identified by a social security number, and also have
a name. Users can access the computers assigned to them; users are guaranteed
access to at least one computer. For each computer that a user may access, the user
is assigned a user-id and a password.
UCS ER Diagram (Conceptual Data Model)
Feature(s) not captured: The number of computers that are connected to a network
may not exceed the capacity of the network."
