Chapter 6 Flashcards
Object
represents a person, a place, an event, or a transaction that is significant to the information system. an object however, includes data and the processes that affect that data. For example, a customer object has a name, an address, and account number, and a current balance. Customer objects can perform specific tasks, such as placing an order, paying a bill, and changing their address.
attributes
which are characteristics that describe the object. For example, a car has attributes such as make, model, and color. attributes are similar to adjectives that describe the characteristics of an object. the number of attributes depends on the business requirements of the information system and its users
methods
which are tasks or functions that the object performs when it receives a message or command, to do so. for example, a car performs a method called OPERATE WIPERS when it sent a message with the wiper control, and it can APPLY BRAKES when it is sent a message by pressing the brake pedal.
a method defines specific tasks that an object can perform. methods resemble verbs taht describe what and how an object does something
Class-instance
an instance is a specific member of a class. A Toyota Camry, for example, is an instance of the Car class. at an auto dealership many instances of the CAR class may be observed: the TRUCK class, the MINIVAN class, and the SPORT UTILITY VEHICLE class, among others
Relationships
enable objects to communicate and interact as they perform business functions and transactions required by the system. Relationships describe what objects need to know about each other, how objects respond to changes in other objects, and the effects of membership in classes, super classes, and subclasses. some relationships are stronger than others (just as a relationship between family members is stronger than one between casual acquaintances).
Inheritance
The strongest relationship is called inheritance. Inheritance enables an object, called a child, to derive one or more of its attributes from another object, called a parent
