Abstract ER Model

Part 1

With your group, create an ER model for the following requirements:

• An X runs at least one Y, but usually more.
• A Y is uniquely identified by its ID, and may be run by an X.
• A Y has an address.
• A Z is uniquely identified by its ID and has an email.
• An X can grow many Z’s.
• A Z is grown by exactly one X.
• An R is identified by its name and has a size.
• A Y always stands on a single R.
• Only one Y can stand on an R, but an R doesn’t have to have a Y standing on it.

Part 2

With your group, extend the model you created in Part 1 to include the following requirements:

• A Z holds at least one W.
• The W’s that each Z holds are consecutively numbered starting at 1.
• X’s can eat many Z’s.
• Z’s can be eaten by many X’s.
• An R may control other R’s.
• An R may or may not be controlled by another R.