What is a Class Diagram?

A variety diagram models the static structure of a system. It fork outs relationships in the midst of fall apartes, objects, attributes, and operations.Basic Class Diagram Symbols and NotationsClassesClasses represent an abstraction of entities with common characteristics. associations represent the relationships in the midst of secernes.Illustrate classes with rectangles divided into compartments.Place the name of the class in the first naval division (centered, bolded, and capitalized), list the attributes in the second partition (left-aligned, not bolded, and lowercase), and write operations into the third. Active ClassesActive classes initiate and control the flow of activity, date passive classes inventory data and serve early(a) classes. Illustrate sprightly classes with a thicker border. Visibility physical exercise visibleness markers to signify who layabout entrance fee the in shaping contained within a class. individual(a) visibility, denoted with a sign, hi des information from anything outside the class partition. Public visibility, denoted with a + sign, whollyows all other classes to view the marked information. Protected visibility, denoted with a sign, allows nipper classes to access information they inherited from a parent class. AssociationsAssociations represent static relationships among classes. Place association names preceding(prenominal), on, or below the association demarcation line.Use a change arrow to indicate the direction of the relationship. Place roles surface the end of an association. Roles represent the way the two classes see each other. numerousness (Cardinality)Place multiplicity notations near the ends of an association. These symbols indicate the number of instances of matchless class linked to unrivalled instance of the other class. For example, unmatchable company will have wizard or more employees, but each employee works for that one company. make-up and AggregationComposition is a specia l type of accumulation that denotes a strong willpower surrounded by Class A, the whole, and Class B, its part.Illustrate composition with a filled diamond. Use a hollow diamond to represent a saucer-eyed accruement relationship, in which the whole class plays a more of the essence(predicate) role than the part class, but the two classes are not subordinate on each other. The diamond ends in both composition and aggregation relationships point toward the whole class (i.e., the aggregation).GeneralizationGeneralization is some other name for inheritance or an is a relationship. It refers to a relationship between two classes where one class is a specialized version of other.For example, Honda is a type of car. So the class Honda would have a generalization relationship with the class car. In satisfying life coding examples, the difference between inheritance and aggregation can be confusing. If you have an aggregation relationship, the aggregate (the whole) can access compl etely the PUBLIC functions of the part class. On the other hand, inheritance allows the inheriting class to access both the PUBLIC and PROTECTED functions of the superclass. https//www.smartdraw.com/uml-diagram/5.Describe the six (6) contrastive relationship notation that exists in UML Class Diagram? (6 Marks)Answer Relationships in Class DiagramsClasses are interrelated to each other in item ways. In particular, relationships in class diagrams include different types of logical connections. The adjacent are such types of logical connections that are possible in UML Association Directed Association Reflexive Association Multiplicity Aggregation Composition Inheritance/Generalization RealizationAssociationis a broad term that encompasses just about any logical connection or relationship between classes. For example, passenger and airline may be linked as above Directed Associationrefers to a directional relationship represented by a line with an arrowhead. The arrowhead depicts a container-contained directional flow. Reflexive AssociationThis occurs when a class may have multiple functions or responsibilities.For example, a staff member working(a) in an airport may be a pilot, aviation engineer, a ticket dispatcher, a guard, or a keep crew member. If the maintenance crew member is managed by the aviation engineer there could be a managed by relationship in two instances of the same class. Multiplicityis the active logical association when the cardinality of a class in relation to another is being depicted. For example, one fleet may include multiple airplanes, while one commercial airplane may contain zero to many an(prenominal) passengers. The notation 0..* in the diagram means zero to many Aggregationrefers to the formation of a particular class as a result of one class being aggregated or built as a collection.For example, the class depository library is made up of one or more books, among other materials. In aggregation, the contained classes are not strongly dependent on the lifecycle of the container. In the same example, books will remain so even when the library is dissolved. To institute aggregation in a diagram, draw a line from the parent class to the child class with a diamond inning near the parent class. CompositionThe composition relationship is very similar to the aggregation relationship. with the only difference being its key purpose of emphasizing the colony of the contained class to the life cycle of the container class. That is, the contained class will be obliterate when the container class is destroyed.For example, a shoulder bags side pocket will to a fault cease to exist once the shoulder bag is destroyed. Inheritance / Generalizationrefers to a type of relationship wherein one associated class is a child of another by virtue of assuming the same functionalities of the parent class. In other words, the child class is a specific type of the parent class.To show inheritance in a UML diagram, a straight li ne from the child class to the parent class is drawn using an unfilled arrowhead. Realizationdenotes the executing of the functionality defined in one class by another class. To show the relationship in UML, a broken line with an unfilled solid arrowhead is drawn from the class that defines the functionality to the class that implements the function. In the example, the printing preferences that are sink using the printer setup interface are being employ by the printer. https//creately.com/blog/diagrams/class-diagram-relationships/6. Provide the list of six (6) Multiplicity timidity?ANSWERMultiplicityMultiplicity is a definition of cardinality i.e. number of elements of some collection of elements by providing an inclusive interval of non-negative integers to specify the allowable number of instances of described element. Multiplicity interval has some lower bound and (possibly infinite) speed boundmultiplicity-range = lower-bound .. upper-bound lower-bound = natural-value- specification upper-bound = natural-value-specification *Lower and upper bounds could be natural constants or constant expressions evaluated to natural (non negative) number. top(prenominal) bound could be also specified as asterisk * which denotes unlimited number of elements. Upper bound should be greater than or mates to the lower bound