30-03-2012, 12:39 PM
Analysis Model
ANALYSIS MODEL.ppt (Size: 451.5 KB / Downloads: 93)
Outline
Basic concept of analysis model
Data model
ER model
Object model
Functional model
Data flow model
Behavioral model
State transition model
System behavior modeling with sequence diagram
Objectives of Analysis Model
Objectives of analysis model
To describe what the customer require
To establish a basis for the creation of a software design
To define a set of requirements that can be validated once the software is built
Model
What is a model?
a model is a simplification of reality
Why do we model?
we build models so that we can better understand the system we are developing
we build models of complex systems because we cannot comprehend such a system in its entirety
four aims to achieve
help us to visualize a system
permit us to specify the structure/behavior of a system
give us a template that guides us in constructing systems
document the decisions we have made
Object models
Object = entity (in ERD) + operations
Object models describe the system in terms of object classes
An object class is an abstraction over a set of objects with common attributes and the services (operations) provided by each object
Various object models may be produced
Inheritance models
Aggregation models
Interaction models
Object models
Natural ways of reflecting the real-world entities manipulated by the system
Object class identification is recognised as a difficult process requiring a deep understanding of the application domain
Object classes reflecting domain entities are reusable across systems
Inheritance models
Organise the domain object classes into a hierarchy
Classes at the top of the hierarchy reflect the common features of all classes
Object classes inherit their attributes and services from one or more super-classes. these may then be specialised as necessary
Object Aggregation
Aggregation model shows how classes which are collections are composed of other classes
Similar to the part-of relationship in semantic data models
System behaviour modelling with Sequence Diagram
A behavioural model shows the interactions between objects to produce some particular system behaviour that is specified as a use-case
Sequence diagrams (or collaboration diagrams) in the UML are used to model interaction between objects