1 / 33

Object Oriented Business Modelling, Systems Analysis, and Systems Design (IS 2204 )

Object Oriented Business Modelling, Systems Analysis, and Systems Design (IS 2204 ). 15/9/14 Introduction to systems development. Dr. Ciara Heavin Business Information Systems. Lifecycle and methodology: Learning Outcomes. After completing these lectures students should be able to:

faunia
Download Presentation

Object Oriented Business Modelling, Systems Analysis, and Systems Design (IS 2204 )

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Object Oriented Business Modelling, Systems Analysis, and Systems Design (IS2204) 15/9/14 Introduction to systems development Dr. Ciara Heavin Business Information Systems

  2. Lifecycle and methodology: Learning Outcomes After completing these lectures students should be able to: • Define the concept of systems development methodology and explain its role • Understand the importance of requirements and their analysis • Discuss the characteristics of various types of systems development methodologies such as data-driven, OO and Agile • Define the concepts of model and diagram and explain their role in the systems development process • Identify various types of models used in IS development 2nd year BIS / IS2204

  3. Recap: Information systems in business and management • Information as a resource • How is it managed? • Technological background • and related change • Users • Influence (internal or environmental) • Form of information: detailed vs. summarized • Functionality 2nd year BIS / IS2204

  4. Recap: Information systems development • Understand business processes • And their environment (they exist in) • Analyse and Model • Feedback • Design system • Develop and construct • Install (put into use) • Maintain • Improve 2nd year BIS / IS2204

  5. (Business/Management) Information Systems • “information” has many definitions • “information systems” have just as many • The integration and relationships of People, processes, data and technology • Hardware – software – data – procedures – people (Kroenke) • Organizations, management and technology (Laudon) 2nd year BIS / IS2204

  6. Why study MIS/BIS • To understand technology and its • development, • management (operations) and • use • Consider and understand its (potential and actual) impact • Be able to assess future trends, evaluate how they might affect businesses, and apply them successfully 2nd year BIS / IS2204

  7. Systems by functional areas • Predictions • (coupled w/ accounting) • Supplier • (coupled w/ manufacturing) • Sales – Customers • (coupled w/ marketing) • Learning • (coupled w/ HR) • Accounting • Manufacturing • Marketing • Human Resource • Integration : ERP 2nd year BIS / IS2204

  8. The lifecycle of a system • Development • SDLC: analysis, design, construction, implementation • Management (operations) and maintenance • Installation • Use • Revisions • Decommissioning 2nd year BIS / IS2204

  9. This module focuses on: the development of systems • Participants • Roles • Management • Analysts • SMEs • … • Process • Methodology • Phases • Work products • Models • Project • Teamwork • Planning • Status • Outcome • Product • Solution • (system) • … and its use • Functionality 2nd year BIS / IS2204

  10. Definition : Analysis & Design • Analysis : what users need the system to do • Expressed through models • Depicted in diagrams • Design : how the system will meet the need 2nd year BIS / IS2204

  11. Analysis = listening Intimidated users => confusion 2nd year BIS / IS2204

  12. Design = making decisions It is difficult to understand users’ expectations 2nd year BIS / IS2204

  13. Understanding requirements ... • Analysing problems • Narrative (what the situation is, what the problem is about) • Activity diagram • Context diagrams (e.g. level 0 DFD) • Use cases (OO) • Functional decomposition • Process specification • Data flow diagrams (level 1 and below) • Entity relationship model • Object model (with domain objects) • Designing solutions • Data schema • Application specifications • Object model with design objects • UI 2nd year BIS / IS2204

  14. System Development Methodology Formal and precise process • Driving principles and a set of related techniques • Activities, methods, practices • E.g. to evaluate the costs and benefits of different solutions • Organized into a series of phases • Set of defined deliverables • A corresponding set of tools • Serving various participants and their needs • Project management tools • Modelling tools • Development management tools 2nd year BIS / IS2204

  15. OO approach • Used for systems where • changes to data structure or processes are more frequent • Neither data nor process “heavy” • There is “green field” development (no legacy issues) • Puts reusability and data protection to the driver’s seat • No “common” (shared) data • Working with the same type of data (re)uses same code • Models can turned into code through clear, step-by-step transformations 2nd year BIS / IS2204

  16. Development mindset THE world (problem) Construction SDLC reality Impl. model system (env.) requirements user requirements language feedback, test, QA its model code Use, maintenance feasibility Design /UI high level documentation Project management low level s/w 2nd year BIS / IS2204

  17. Model • A Model is a simplified representation of a complex reality, usually for the purpose of understanding that reality, and having the features of that reality necessary for the current task or problem • Modelling is a form of abstraction -the process of focusing on those features that are essential for the task at hand and ignoring those that are not • Models are usually captured in the form of a diagram, thus a visual representation of the model 2nd year BIS / IS2204

  18. Logical vs. Physical models • Logical models show what a system is or does. They are implementation independent. • Physical models show not only what a system is or does, but also how the system is physically and technically implemented. 2nd year BIS / IS2204

  19. Building a model • Functional decomposition • Context diagram • Data Flow Diagram • Context level • Processes • Data Flow • Data store • External entities • (system interfaces or human actors) 2nd year BIS / IS2204

  20. Functional Decomposition Diagram • Decomposition is the art of breaking a system into its component subsystems, processes, subprocesses. Each level of abstraction reveals more or less detail about the overall system or a subset of that system • a decomposition diagram shows the top-down functional decomposition and structure of a system 2nd year BIS / IS2204

  21. Context diagram • WHAT IS THE CONTEXT IN WHICH THE SYSTEM IS USED • THIS WILL IDENTIFY THE MAIN INTERNAL & EXTERNAL DIMENSIONS OF THE SYSTEM Global Airline seat booking On-line reservation system Internet Users 2nd year BIS / IS2204

  22. Data Flow Model • Goal, purpose • Process modelling concept • Depicts the flow of data through a system and the work or processing performed by that system • (Also called process model) • Context level • Level 1 • Level 2 • A Data Flow Diagram (DFD) is a graphical tool • Components • Notation 2nd year BIS / IS2204

  23. DFDs Entity • Function • Process • Data • Various notations… • DFC • Gane-Sarson customer transaction Process (Execute transaction) Data store 2nd year BIS / IS2204

  24. DFDs • Function • Process • Data • Various notations… • DFC • Gane-Sarson Entity customer transaction Process (Execute transaction) Data store 2nd year BIS / IS2204

  25. Flowcharts • System Flowcharts are diagrams • that show the flow of control through a system • while specifying all programs, inputs, outputs, • and file/databases accesses and retrievals • as well as steps and decision points in a process 2nd year BIS / IS2204

  26. 2nd year BIS / IS2204

  27. Example : www.ryanair.com 2nd year BIS / IS2204

  28. Functional decomposition 2nd year BIS / IS2204

  29. Context level DFD Customer Provides travel details Global Airline seat booking Provides options Makes booking w/ payment 2nd year BIS / IS2204

  30. Example : www.ryanair.com • Input : • Flight details (eg. SNN-BVA, 8 Oct, 10.35) • Credit card details (eg. VISA no, Expiry date) • Process : • Confirms price (eg. EUR 79) • Makes reservation • processes payment • Output : • Reservation reference (eg.CGHKCA) 2nd year BIS / IS2204

  31. ERDs • Data modelling concept • Entity • With attributes • And their relationship(s) • Cardinality and Degree • Min-max • Number of entities in a relationship • Cardinality and Modality • Max # • 0 or 1 min at the instance level (does 1 have to exist?) 2nd year BIS / IS2204

  32. Entity relationship diagrams • ERD’s are used to illustrate the logical structure of databases Attribute Attribute Attribute Relationship Entity Entity Attribute Attribute 2nd year BIS / IS2204

  33. Sample ERD 2nd year BIS / IS2204

More Related