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ZEIT2301 Design of Information Systems Unified Modelling Language. School of Engineering and Information Technology UNSW@ADFA Dr Kathryn Merrick. Topic 03: Models and System Design. Objectives To consider the role of modelling in system design and development.
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ZEIT2301Design of Information SystemsUnified Modelling Language School of Engineering and Information Technology UNSW@ADFA Dr Kathryn Merrick
Topic 03: Models and System Design • Objectives • To consider the role of modelling in system design and development. • Refresh knowledge of UML and object-oriented approach to systems development References Text: Ch 5
The role of modelling in software development • “Modellingis the designing of software applications before coding. Modelling is an essential part of large software projects, and helpful to medium and even small projects as well. A model plays the analogous role in software development that blueprints and other plans (site maps, elevations, physical models) play in the building of a skyscraper.” • OMG (Object Modelling Group) http://www.omg.org/gettingstarted/what_is_uml.htm
Why create models? • Modelling should be a dynamic process • Bring together developers, users and stakeholders • Spur refinement and expansion of requirements • Document what was done for future reference • Promote informal training • Model development tools • Simple implements such as pencil and paper • Sophisticated tools such as CASE
Unified Modelling Language • Provides a common vocabulary of object-oriented terms and diagramming techniques rich enough to model any systems development project from analysis through to implementation • Version 2.0 has 14 diagrams in 2 major groups: • Structure diagrams • Behaviour diagrams
UML Structure Diagrams • Represent the data and static relationships in an information system • Class • Object • Package • Deployment • Component • Composite structure
UML Behaviour Diagrams Depict the dynamic relationships among the instances or objects that represent the business information system • Activity • Sequence • Communication • Interaction Overview • Timing • Behavioural State Machine • Protocol State Machine • Use case
UML and development methodologies • UML is not a development methodology. It is a set of notations and diagrams for modelling a system. • Various methodologies, some proprietary, use UML. • The Unified Process (UP) for example is an object-oriented system development methodology which uses UML for modelling.