CHAPTER 7: STRUCTURING
SYSTEM PROCESS REQUIREMENTS
• Overview of process modeling, DFDs, BPMN, and analysis
techniques.
LEARNING OBJECTIVES
• • Model processes using Data Flow Diagrams (DFDs)
• • Understand DFD symbols and rules
• • Apply decomposition and balancing
• • Differentiate DFD types
• • Use BPMN basics
WHAT IS A DATA FLOW DIAGRAM
(DFD)?
• A visual representation of how data moves through a
system.
• Shows processes, data stores, and external entities.
BASIC DFD COMPONENTS
• • Process: transforms data
• • Data Flow: movement of data
• • Data Store: data repository
• • Source/Sink: external entity
DFD RULES
• • Processes must have inputs and outputs
• • Data flows in one direction
• • No direct flow between stores/entities
• • Use meaningful labels
DECOMPOSITION
• Breaking a system into smaller subsystems.
• Creates multiple levels of detail (Level-0, Level-1, etc.).
BALANCING
• Ensures inputs and outputs remain consistent
• across different levels of DFDs.
TYPES OF DFDS
• • Current Physical
• • Current Logical
• • New Logical
• • New Physical
CONTEXT DIAGRAM
• Highest-level DFD.
• Represents system as a single process
• with external interactions.
DFD LEVELS
• • Context Diagram
• • Level-0 Diagram
• • Level-1, Level-2 (decomposition continues)
DFD GUIDELINES
• • Completeness
• • Consistency
• • Timing
• • Iterative development
BUSINESS PROCESS MODELING
(BPM)
• Models workflows in a business.
• Focuses on activities, decisions, and flow.
BPMN KEY ELEMENTS
• • Event: trigger
• • Activity: task
• • Gateway: decision
• • Flow: sequence
DECISION TABLES
• Used to represent complex logic.
• Includes conditions, actions, and rules.
USING DFDS IN ANALYSIS
• • Identify inefficiencies
• • Improve system design
• • Ensure completeness
• • Compare alternatives
KEY TAKEAWAYS
• • DFDs are essential for system modeling
• • Decomposition adds clarity
• • BPMN complements DFDs
• • Tools support analysis and design