A “Whack-The-Balls” session: Every Friday the manager of Whack-The-Balls arranges the playing sessions for the week beginning in 4 weeks time. At the same time, the records of playing sessions from 4 weeks ago are deleted. Each session is booked either by a team or a member. The booking may subsequently be cancelled, in which case it will become available for re- booking. When the team or member arrives to play on the booked court the session is marked as ‘played’. The EEM for Whack-The-Balls records the following events for the “session” entity… - Make team booking(M) - Make member booking(M) - Cancel booking(M) - Play session(M) - Arrange sessions(C/D) PRODUCE AN ELH FOR A WHACK-THE-BALLS SESSION.

SESSION ARRANGE NEW SESSION MANAGE SESSION USE SESSION DELETE OLD SESSION * BOOK SESSION MAKE TEAM BOOKING MAKE MEMBER BOOKING CANCEL CANCEL TEAM BOOKING CANCEL MEMBER BOOKING MARK AS PLAYED oo ooo o

IO Structure Diagram (I/OSD) BOOK SESSION GET BOOKING DATA ISSUE RESPONSE INDIVIDUAL DATA (input) TEAM DATA (input) oo CONFIRMATION (output) REJECTION (output) oo

A (disjoint) I/OSD Example Loan status Data of copies

Event Entity Matrix (EEM) Example Event

EEM Views Event

The ELH View (for entity “Reader”) Comm. with reader

The ECD View (for event “Lend”)

Produce an ECD for the event “ARRANGE SESSION” (could be old or new).

NEW SESSION OLD SESSION SET OF EQUIPMENT BOOKING EQUIPMENT BOOKING * Session Number

Produce an I/O structure diagram for the following “Whack-The-Balls” enquiry function description. “When a playing court number is entered into the system it should return a list of all the sessions for which the court has been booked, giving details of the member or team that placed each booking”. Assume the following attribute names are required… –Court # –Session # –Session start time –Session end time –Member # –Member name –Team # –Team name

LDS for “Whack-The-Balls” scenario: TeamSportCourt Price Band Member Session Equipment contains played in hosts assigned to booked for requires use of plays played by tagged to is within made up of component of books booked by books played by plays used by consumed on

Produce an EAP for the “Whack-The-Balls” court number enquiry report (from a previous slide), using the LDS from the immediately previous slide.

SET OF SESSION COURT Court # SESSION * TEAM BOOKED BY TEAM o BOOKED BY MEMBER o Member

CONSIDER THE FOLLOWING TABLE: Customer Order Customer Order # Customer # Customer Name Customer Address Customer Tel. # Depot # Depot Name Product # Product Name Product Qty Product Price ANY COMMENTS?...

1NF = no repeating groups. Customer Order # Customer # Customer Name Customer Address Customer Tel. # Depot # Depot Name Customer Order # Product # Product Name Product Qty Product Price

2NF = 1NF + no non-key attributes which are dependent on only part of the primary key. Customer Order # Customer # Customer Name Customer Address Customer Tel. # Depot # Depot Name Customer Order # Product # Product Qty Product # Product Name Product Price

3NF = 2NF + no non-key attributes which are dependent on other non-key attributes. Customer Order #Customer Order * Customer # * Depot # Customer #Customer Details Customer Name Customer Address Customer Tel. # Depot #Depot ID Depot Name Customer Order #Customer Order Line Product # Product Qty Product #Product Details Product Name Product Price

Another ELH Example (1) System 1 description: The system should manage boats taking part in a club tournaments. The system should allow boats to be registered and de-registered, as well as editing of their details. Furthermore, the system should allow the allocation and de- allocation of boats to races. Only boats registered in the system can participate in races. Registered boats can have their details and their race allocations edited any number of times. boat register boat de-register boat edit boat details allocate boat to race * oo

Another ELH Example (2) System 2 description: The system describes the movement of a lift to service a call. On receipt of a call and if the lift is idle, the lift will leave the floor at which it is located and proceed to next floor (either up or down). On arrival at a floor, the lift will either stop, if that is where the call originated from, or proceed with its movement. Once the lift stops at a floor, another call will make it leave that floor. lift leave initial floor arrive at floor leave current floor stop at floor- * oo

Interpreting an ELH student Student registration Enrol in module Withdraw from module * oo Amend student det. Premature departure Course completed Student departs o oo 1 year after student dep. Student permanence Student actions Student departure Normal departure