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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.