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the shed in volume (cubic feet). There is also a tax
calculation formula that differs for each of the four
building types.
2. Draw an object-oriented class diagram, including
traditional unary, binary and ternary relationships,
as well as generalization and aggregation relation-
ships as needed, to represent the following business
environment. Include all the attributes and opera-
tions listed in the description.
Reliable Home Warranty Company contracts
with homeowners to repair their major appliances,
electrical systems, and plumbing, all for a single
annual fee. When a homeowner needs a repair,
he calls Reliable and speaks to a dispatcher who
sends a qualified technician from a participating
repair company. The participating repair company
then charges Reliable for the repair. Each dispatcher
has an employee number, name, home address,
and home telephone number. Each homeowner
has a contract number, name, home address, home
telephone number, and contract renewal date. Each
job has a unique job number, date, and time. Each
job is handled by one dispatcher and (obviously)
involves one homeowner.
There are three kinds of jobs: appliance repair,
electrical repair, and plumbing repair. For an
appliance repair, the company wants to record the
appliance type, its model number, its serial number,
and the name of the appliance repair company
assigned. In addition, Reliable wants to keep track
of the manufacturer of the appliance. For each
appliance manufacturer it lists the manufacturer
name, headquarters address, and telephone number
for parts ordering. There is a calculation for the
charge that the appliance repair company makes to
Reliable based on the type of appliance and the
time spent. For a plumbing repair, Reliable keeps
track of the name of the plumbing company and
the length of time for the repair, but beyond that
it makes a distinction between inside repairs and
outside repairs such as to sewer lines or septic
tanks. Charges from the plumbing company to
Reliable are based on a specific plumbing charge
formula, but are calculated differently depending on
whether the repair is an inside or outside repair.
Also, for outside repairs, Reliable must record the
distance from the house to the main sewer line
or septic tank. For an electrical repair, Reliable
tracks the length of time for the repair and the
amount and type of wire used in the repair. There
is a formula for calculating electrical repair charges
based on time and the specialized materials used.
Reliable must also keep certain information about
the electrical contracting company assigned to the
repair. This information includes the contractor's
license number, name, address, and liability insurer.
A particular electrical contracting company can be
involved in many repairs.
MINICASES
1.
In Minicase 1 of Chapter 2, you were asked to draw an
entity-relationship diagram describing Happy Cruise
Lines' business environment. We now report that
Happy Cruise Lines has been acquired by MegaShip
Lines, Inc., which has a fleet of oil tankers, container
ships, and automobile transport ships. Thus, with the
addition of Happy's cruise ships, MegaShip Lines will
have four kinds of ships.
a. Draw an object-oriented generalization diagram,
including aggregation relationships as needed, to
represent MegaShip's new business environment,
with the following attributes and operations. All of
MegaShip's ships have ship number, ship name,
year built, weight, miles traveled, and next overhaul
date attributes. In addition, cruise ships have
passenger capacity and next health inspection date;
oil tankers have oil capacity, container ships have
number of containers, and automobile transport
ships have number of automobile attributes. An
operation determines the next overhaul date for all
of the ships in the same manner. Another operation
determines the next health inspection date for cruise
ships. An operation calculates the next date for a
ship to be refueled. This operation is the same for oil
tankers, container ships, and automobile transport
ships, but is different for cruise ships because of
safety precautions regarding the passengers. Oil
tankers are composed of a hull, one or more
engines, and one or more oil storage tanks. An
attribute of hull is length, an attribute of engine is
horsepower, and an attribute of oil storage tank is
capacity.
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