UML Primitive Modeling Elements

Question 1

What is UML

Answer 1

Unified modelling language is a visual language for representing data models.
It was first developed in 1990 and widely used since 2000 and iso standard
It is diagram based
Used for human-human communication

Question 2

What is a use case diagram?

Answer 2

Takes the actors perspective to communicate requirements of functionality, what needs to be done

Question 3

What is a UML class diagram?

Answer 3

It destructive a the structure of a data model by visualising classes their methods, attributes and relations to other classes

Question 4

How do UML class diagrams show inheritance?

Answer 4

Class b inherits the properties attributes, methods of class a
Everything that holds true for a holds true for b
White triangle points towards a from b
Is a transitive relation

Question 5

What other relationships can UML class diagrams show

Answer 5

Association- a named uni or bi directional link between classes
 Aggregation - class a is the whole class b contains part(open white diamond points to a)
- if one prt of an aggregation is deleted the whole is not necessarily deleted, if the whole is deleted the part may not jbe
Composition - a stronger form of aggregation. The parts and the whole depend on each other

Question 6

example of UML CLASS DIAGRAM RELATIONSHIPS

Answer 6

Aggregation- the class airport is an aggregation of the classes runway, hangar and terminal
Composition - a polygon and it’s component arcs and nodes

Question 7

What symbols are used for multiplicity in UML Class diagrams

Answer 7

0...1 no instance or one
1 always 1 
0 *or* ... zero or more instances 
1 *or* one or more instances
1:1 one-to-one cardinality
1:n One to many cardinality
M:n any number to any number