ZEIT2301- Design of Information Systems ZEIT2301 Design of IS Week 01: Intro ZEIT2301- Design of Information Systems School of Engineering and Information Technology UNSW@ADFA Dr Kathryn Merrick Session 2, 2010

ZEIT2301 Design of IS Week 01: Intro Week 01: Intro Topics: Review of the systems development lifecycle (SDLC) and its phases Introduction to the database development lifecycle (DBLC) and phases References: Dennis, A., Wixom, B.and Tegarden, D., Systems Analysis and Design with UML Version 2.0: An Object-Oriented Approach, 3rd edition, 2009, John Wiley. (Chapter 1) Connolly, T., Begg, C., Database Solutions: A step-by-step guide to building databases, Second Edition, Pearson, 2004. (Chapter 4) Session 2, 2010

Systems Development Lifecycle ZEIT2301 Design of IS Week 01: Intro Systems Development Lifecycle The SDLC consists of phases/activities traditionally used to conceive, develop and maintain information systems. Different variants of the lifecycle exist. The textbook identifies four phases Planning, Analysis, Design, Implementation Session 2, 2010

SDLC Phases 1. Planning (actually initiation, then planning) ZEIT2301 Design of IS Week 01: Intro SDLC Phases 1. Planning (actually initiation, then planning) Why build the system? 2. Analysis Who, what, when, where of the system? 3. Design How will the system work? 4. Implementation System delivery Session 2, 2010

1. Planning Identifying business value Evaluate feasibility ZEIT2301 Design of IS Week 01: Intro 1. Planning Identifying business value Does the project align with key business objectives? Evaluate feasibility Technical, economic, organizational Develop work plan Staff the project Control and direct project Session 2, 2010

2. Analysis Requirements Gathering/Elicitation Requirements Modelling ZEIT2301 Design of IS Week 01: Intro 2. Analysis Requirements Gathering/Elicitation Gather the requirements (using various techniques, e.g. interviews, document analysis, etc) Requirements Modelling Develop a set of analysis models that represent both the data and processes necessary to support the business Requirements Specification Document the requirements in a system/software requirements specification document Session 2, 2010

3. Design Develop a design strategy Hardware, software, networks ZEIT2301 Design of IS Week 01: Intro 3. Design Develop a design strategy Design architecture and interfaces Hardware, software, networks Interface design Forms, reports, web pages Database and file design Program design Session 2, 2010

4. Implementation Construction System is built (or acquired) ZEIT2301 Design of IS Week 01: Intro 4. Implementation Construction System is built (or acquired) System testing Installation Implement a training plan for the users New system becomes operational Operation & Maintenance Establish a support plan Session 2, 2010

Processes and Deliverables ZEIT2301 Design of IS Week 01: Intro Processes and Deliverables Process Product Planning Analysis Design Implementation Project Proposal and Plan Requirements Specification Code User Manual Session 2, 2010

Database Development Lifecycle Planning Analysis Design DBMS Selection Implementation Maintenance

1. Planning Management activities that permit the stages of the database system development lifecycle to be realised efficiently and effectively Creation of a mission statement and objectives Development of standards for data collection and format

2. Analysis Collecting and analysing information about the organisation to be supported by the new database system Using this information to identify the requirements of the new database A preliminary part of database design

3. Database Design Creating a design that will support the organisation’s mission statement and objectives Other design processes: Application design Transaction design User interface design

Database Management Software Shared collection of logically related data Applications Interact with database via DBMS Database Management Software (DBMS) Methods to define, retrieve update and maintain data

4. DBMS Selection

5. Implementation Physical realisation of the database and related applications Includes data conversion and loading Testing

6. Maintenance Monitoring and maintaining the database system following installation

Systems development: Some terminology ZEIT2301 Design of IS Week 01: Intro Systems development: Some terminology Methodology: A comprehensive approach to system development; typically includes activities, techniques, and tools Technique: a collection of guidelines that help an analyst complete an activity or task Tool: a specific device, usually software, which makes it easier to use a specific technique Session 2, 2010

System Development Methodologies ZEIT2301 Design of IS Week 01: Intro System Development Methodologies Historically methodologies tended to be either process-centred or data-centred. More recently the object-oriented approach seeks to integrate both process and data in a single model. Large organizations may follow internal methodologies or formal standards. For a complex information system, a systematic approach is crucial. Well-known methodologies include: Waterfall development Parallel development Rapid application development Agile development Session 2, 2010

Categories of Methodologies ZEIT2301 Design of IS Week 01: Intro Categories of Methodologies Structured Design Waterfall Development Parallel Development Rapid Application Development Phased Prototyping Throwaway Prototyping Agile Development eXtreme Programming Session 2, 2010

ZEIT2301 Design of IS Week 01: Intro “Structured” Design The advent of “Structured” design introduced formal models: Typically used one set of models to describe process (eg Data Flow Diagrams) and a separate set of models to describe data (eg Entity-relationship Diagrams) Structured development methodology involved a formal step-by-step approach Most well known methodology is the Waterfall method Moves from one phase to the next in sequence Many variants; later variants allowed for iteration where necessary Session 2, 2010

Structured Design 1 Waterfall Development ZEIT2301 Design of IS Week 01: Intro Structured Design 1 Waterfall Development Session 2, 2010

Pros and Cons of the Waterfall Method ZEIT2301 Design of IS Week 01: Intro Pros and Cons of the Waterfall Method Pros Cons Identifies systems requirements long before programming begins Requirements must be fully specified before programming begins Long delay before delivery of product; Highly formalized; Inflexible; Session 2, 2010

Structured Design 2 Parallel Development: sub-projects ZEIT2301 Design of IS Week 01: Intro Structured Design 2 Parallel Development: sub-projects developed separately Session 2, 2010

Pros and Cons of Parallel development ZEIT2301 Design of IS Week 01: Intro Pros and Cons of Parallel development Pros Cons Divides project into sub-projects that can be worked on in parallel thus allowing earlier delivery of the system Subsystems might not be independent; could require significant integration effort Session 2, 2010

Rapid Application Development ZEIT2301 Design of IS Week 01: Intro Rapid Application Development Rapid Application Development (RAD) Concentrates on developing at least part of the system much earlier Involving users for feedback Use of tools to speed development Session 2, 2010

Rapid Application Development ZEIT2301 Design of IS Week 01: Intro Rapid Application Development Key features CASE tools (Computer-Aided Software Engineering) JAD sessions (Joint Application Development) Fourth generation/visualization programming languages Code generators Eg generate code from models/diagrams Session 2, 2010

RAD based approaches Phased Development Prototyping ZEIT2301 Design of IS Week 01: Intro RAD based approaches Phased Development A series of versions; initial version meets key requirements Prototyping System prototyping Prototype evolves to become the system Throw-Away Prototyping Design prototyping Prototype is used only to help determine requirements Session 2, 2010

Rapid Application Development 1 ZEIT2301 Design of IS Week 01: Intro Rapid Application Development 1 Phased Development Version1, version 2, etc Session 2, 2010

Rapid Application Development 2 ZEIT2301 Design of IS Week 01: Intro Rapid Application Development 2 System Prototyping The prototype evolves to become the actual system Session 2, 2010

Rapid Application Development 3 ZEIT2301 Design of IS Week 01: Intro Rapid Application Development 3 Throwaway Prototyping The prototype is only used to help elicit requirements and thus inform system design. Session 2, 2010

Agile Development Agile development Extreme Programming ZEIT2301 Design of IS Week 01: Intro Agile Development Agile development Drastically reduces the modelling and associated documentation phases Concentrates on programming (ie producing working code) Extreme Programming Develop code rapidly and involve users Pair programming using skilled programmers Rapid incremental development; continuous release of product to users Session 2, 2010

Agile Development Extreme Programming ZEIT2301 Design of IS Week 01: Intro Agile Development Extreme Programming Session 2, 2010

Criteria for Selecting the Appropriate Methodology ZEIT2301 Design of IS Week 01: Intro Criteria for Selecting the Appropriate Methodology Clarity of user requirements Familiarity with technology System complexity System reliability Short time schedules Schedule visibility Session 2, 2010

Criteria for selecting a Methodology ZEIT2301 Design of IS Week 01: Intro Criteria for selecting a Methodology Criteria Waterfall Parallel Phased Prototyping Throwaway Prototyping Extreme Programming Unclear user requirements Poor Good Excellent Unfamiliar technology Complex systems Reliable systems Short time schedule Schedule visibility Session 2, 2010

Object-Oriented Analysis & Design ZEIT2301 Design of IS Week 01: Intro Object-Oriented Analysis & Design Attempt to balance emphasis on data and process Uses Unified Modelling Language (UML) Characteristics of OOAD: Use-case Driven Architecture Centric Iterative and Incremental Session 2, 2010

Skills of the systems analyst ZEIT2301 Design of IS Week 01: Intro Skills of the systems analyst Analytical systems thinking, organisational knowledge, problem identification, problem analyzing and solving Technical Computers, networks, databases, operating systems, Internet, programming languages Management Resource management, project management, risk management, change management Interpersonal Communications skills, ability to work in a team, group facilitation, managing expectations Session 2, 2010

The Analyst’s Approach to Problem Solving ZEIT2301 Design of IS Week 01: Intro The Analyst’s Approach to Problem Solving Session 2, 2010

Project Team Roles Role Responsibilities Business Analyst ZEIT2301 Design of IS Week 01: Intro Project Team Roles Role Responsibilities Business Analyst Analyzing the key business aspects of the system Identifying how the system will provide business value Designing the new business processes and policies Systems Analyst Identifying how technology can improve business processes Designing the new business processes Designing the information system Ensuring the system conforms to IS standards Infrastructure Analyst Ensuring the system conforms to infrastructure standards Identifying infrastructure changes required by the system Change Management Analyst Developing and executing a change management plan Developing and executing a user training plan Project Manager Managing the team Developing and monitoring the project plan Assigning resources Serving as the primary point of contact for the project Session 2, 2010

ZEIT2301 Design of IS Week 01: Intro Summary The SDLC consists of four stages: Planning, Analysis, Design, and Implementation The DBLC consists of six stages: Planning, Analysis, Design, DBMS Selection, Implementation, Maintenance System development methodologies vary The choice of an appropriate methodology depends on the characteristics of the system, the organisation and the available staff skill set. Session 2, 2010