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System Analysis

System Analysis and Design. System Analysis. - Mr. Ahmad Al-Ghoul. Learning Objectives. Explain relationships among objects and the concept of inheritance Explain an object relationship diagram

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System Analysis

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  1. System Analysis and Design System Analysis - Mr. Ahmad Al-Ghoul

  2. Learning Objectives • Explain relationships among objects and the concept of inheritance • Explain an object relationship diagram • Describe Unified Modeling Language (UML) tools and techniques, including use cases and use case diagrams System Analysis and Design System Analysis

  3. Object-Oriented analysis and design using UML • Relationships • Enables objects to communicate and interact as they perform business functions and transactions required by the system • Relationships describe what objects need to know about each other • Relationships describe how objects respond to changes in other objects • Relationship describe the effects of membership in classes, super-classes, and subclasses • Inheritance enables an object, called a child, to derive one or more of its attributes from anther object, called a parent • A child object, however, may have additional attributes • The inherited attributes from the parent object do not need to be repeated in the child object System Analysis and Design System Analysis

  4. Object-Oriented analysis and design using UML [1] An inheritance relationship exists between the INSTRUCTOR and EMPLOYEE objects. The INSTRUCTOR (child) object inherits characteristics from the EMPLOYEE (parent) class and can have additional attributes of its own. System Analysis and Design System Analysis

  5. Object-Oriented analysis and design using UML • Relationships Among Objects and Classes • Object Relationship Diagram • After you identify the objects, classes, and relationships, you are ready to prepare an object relationship diagram that will provide an overview of the system • You will use that model as a guide as you continue to develop additional diagrams and documentation System Analysis and Design System Analysis

  6. Object-Oriented analysis and design using UML [1] Object relationship diagram for the fitness center. Notice that the model shows the objects and how they interact to perform business functions and transactions System Analysis and Design System Analysis

  7. Object-Oriented analysis and design using UML • Object Modeling with the Unified Modeling Language • The UML uses a set of symbols to represent graphically the various components and relationships within a system • although the UML can be used for business process modeling and requirements modeling, it mainly is used to support object-oriented system analysis and to develop object models System Analysis and Design System Analysis

  8. Object-Oriented analysis and design using UML • Use case modeling • Use Case • A use case represents the steps in a specific business function or process • A use case is a complete sequence of related actions initiated by an actor • An external entity called an actor, initiates a use case by requesting the system to perform a function or process System Analysis and Design System Analysis

  9. Object-Oriented analysis and design using UML • An actor is someone or something that is external to the system, but that is going to interact with the system. • Actors are represented as stick figures. • Action or event represents by an oval with a label that describes the action or event • The line from the actor to the use case is called an association System Analysis and Design System Analysis

  10. Object-Oriented analysis and design using UML • Use Case Diagrams • Applied to analyze functional requirements of the system • Performed during the analysis phase to help developers understand functional requirements of the system without regard for implementation details System Analysis and Design System Analysis

  11. Object-Oriented analysis and design using UML • Use Case Diagrams • Use case diagrams are created to visualize the relationships between actors and use cases • A use case diagram is a summary of several related use cases within a system or subsystem • Use cases represent complete functionality of the system • To create a use cases, you start reviewing the information that you gathered during the requirements modelling phase • Identify the actors and the functions or transactions they initiate for each use case • Develop a use case description in the form of a table System Analysis and Design System Analysis

  12. Object-Oriented analysis and design using UML • Use case description • A use case description documents the name of the use case • Names of the actors • A description of the use case • A step by step list of the tasks and actions required for successful completion • A description of alternative causes of action • Preconditions • Post conditions • assumptions System Analysis and Design System Analysis

  13. Object-Oriented analysis and design using UML [1] The ADD NEW STUDENT use case description documents the process used to add a current student into an existing class. System Analysis and Design System Analysis

  14. Object-Oriented analysis and design using UML • Steps to create a use case diagram • Identify the system boundary, which is represented by a rectangle • Place the use cases on the diagram • Add the actors • Show the relationships System Analysis and Design System Analysis

  15. Object-Oriented analysis and design using UML • Relationships Between Use Cases • Use cases may participate in relationships with other use-cases • Two types • Extends • Adds new behaviors or actions to a use case • Include • One use case references another use case System Analysis and Design System Analysis

  16. Object-Oriented analysis and design using UML [1] • The figure shows a use case diagram for an auto service department which involves customers, service writers who prepare works orders and invoice, and mechanics who perform the work. • the customer actor initiates the use case by requests service. System Analysis and Design System Analysis

  17. Sequence Summary • After you identify the objects, classes, and relationship, you prepare an object relationship diagram that shows the objects and how they interact to perform business functions and transactions • Inheritance enables an object, called a child, to derive one or more of its attributes from anther object, called a parent • UML techniques include use cases and use case diagrams • A use case describes a business situation initiated by an actor, who interacts with the information system • Each use case represents a specific transaction, or scenario • A use case diagram is a visual summary of related use cases within a system or subsystem System Analysis and Design System Analysis

  18. Sequence Summary • In this Sequence we have • Described how to draw an object relationship diagram that shows the objects and how they interact to perform business functions and transactions • Defined the term inheritance • Explained use case that describes a business situation initiated by an actor, who interacts with the information system • Explained use case diagram and described how to draw it System Analysis and Design System Analysis

  19. Reference [1] System Analysis and Design, Sixth Edition Authors: Gary B. Shelly, Thomas J. Cashman and Harry J. Rosenblatt , Publisher: SHELLY CASHMAN SEWIES. [2] system analysis and design, sixth edition Authors: Kenneth E. Kendall and Julie E. Kendall Publisher: Prentice Hall [3] Modern Systems Analysis and Design Third Edition Authors: Jeffrey A. Hoffer , Joey F. George, Joseph S. Valacich Publisher: prentice hall System Analysis and Design System Analysis

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