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 NEWSESSION

MANAGESESSION

USESESSION

DELETE OLDSESSION

*

BOOK SESSION

MAKE TEAMBOOKING

MAKE MEMBERBOOKING

CANCEL

CANCEL TEAMBOOKING

CANCEL MEMBERBOOKING

MARK AS PLAYED ----------o o

o o o o

IO Structure Diagram (I/OSD)

BOOK SESSION

GET BOOKINGDATA

ISSUE RESPONSE

INDIVIDUAL DATA(input)

TEAM DATA(input)

o oCONFIRMATION

(output)REJECTION

(output)

o o

A (disjoint) I/OSD Example

Loanstatus

Data ofcopies

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 SESSIONSET OF

EQUIPMENTBOOKING

EQUIPMENTBOOKING

*

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:

Team Sport Court

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

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 OFSESSION

COURT

Court #

SESSION*

TEAM

BOOKED BYTEAM

oBOOKED 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 NameCustomer AddressCustomer Tel. #Depot #Depot Name

Customer Order #Product #Product Qty

Product #Product NameProduct Price

3NF = 2NF + no non-key attributes which are dependent on other non-key attributes.

Customer Order #Customer Order* Customer #* Depot #

Customer # Customer DetailsCustomer NameCustomer AddressCustomer Tel. #

Depot # Depot IDDepot Name

Customer Order #Customer Order LineProduct #Product Qty

Product # Product DetailsProduct NameProduct 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

registerboat

de-registerboat

edit boatdetails

allocateboat to race

*

o o

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 initialfloor

arrive atfloor

leavecurrent floor

stop at floor -

*

o o

Interpreting an ELH

student

Studentregistration

Enrol inmodule

Withdrawfrom module

*

o o Amendstudent det.

Prematuredeparture

Coursecompleted

Studentdeparts

o

o o

1 year afterstudent dep.

Studentpermanence

Studentactions

Studentdeparture

Normaldeparture