Systems analysis and development CIS210 ch 07

CIS 210 Systems Analysis and Development Week Part I Structuring System Process Requirements Objectives • Upon completion of part I you will be able to: – Understand and be able to explain the concepts related to the logical modeling process – Understand and be able to draw data flow diagrams – Understand and be able to decompose data flow diagrams into lower-level diagrams – Understand and be able to balance higher-level and lowerlevel data flow diagrams – Understand and be able to explain the concepts related to the differences between the four types of DFDs – Understand and be able to explain the concepts related to Oracle’s process modeling tool and with functional hierarchy diagrams Overview • Data Flow Diagrams – – – – Model data flow Data flow relationships Change processes Also called process models Process Modeling • Overview – Data flow diagram is common form • Modeling a Systems Process for Structured Analysis – Analysis team – Organization of information • Deliverables and outcomes – – – – – Context diagram Diagrams of current system Logical data flow diagrams Data flow and functional requirements Entries of all objects in project dictionary Diagramming Mechanics Diagramming Mechanics Diagramming Mechanics • Decomposition of DFDs – – – – – From one system to multiple systems Functional decomposition Iterative process Finer and finer detail Primitive DFD • Balancing DFDs – Balancing inputs and outputs Types of DFDs • Current Physical – People’s names – Positions • Current Logical – Current system reduced to its essence – Data and processes • New Logical – Additional functions – Obsolete functions removed • New Physical – Automated and manual functions Using Data Flow Diagramming in Analysis • DFD Guidelines – – – – – Completeness Consistency Timing considerations The iterative nature of drawing DFDs Primitive DFDs Using Data Flow Diagramming in Analysis • Using DFDs as Analysis Tools – – – – – Gap analysis Redundant data flows Unused data Inefficiencies Current logical vs new logical • Using DFDs in Business Process Reengineering Use Cases • What is a Use Case – – – – Shows behaviors or functionality Set of sequences Use case Actor • Use Case Diagram – Depicted diagrammatically • Written Use Cases Summary • • • • • • • • • Modeling a systems process for structured analysis Data flow diagram symbols Rules governing data flow diagramming Decomposition of DFDs Balancing DFDs The four types of DFDs DFD guidelines Using DFDs as analysis tools Use cases ... will be able to: – Understand and be able to explain the concepts related to the logical modeling process – Understand and be able to draw data flow diagrams – Understand and be able to decompose... Understand and be able to balance higher-level and lowerlevel data flow diagrams – Understand and be able to explain the concepts related to the differences between the four types of DFDs – Understand... relationships Change processes Also called process models Process Modeling • Overview – Data flow diagram is common form • Modeling a Systems Process for Structured Analysis – Analysis team –