SSD Wk3- Process Modeling and Data Flow Diagram Basics

Foundational understanding of process modeling and data modeling, Data modeling symbols

Process Modeling

Graphically representing processes that capture, manipulate, store, and distribute data between a system and its environment.

Data Flow Diagram (DFD)

A visual representation of the flow of information through a process or system, used to understand operations and discover potential problems.

Use Case Diagram

A diagram that captures the interactions between users (actors) and the system, outlining all possible use cases.

Functional Decomposition

An iterative process of breaking down a system description into finer-level details to enhance understanding.

Context Diagram

An overview that shows system boundaries, external entities interacting with the system, and major information flows.

DFD Guidelines

Rules to ensure clarity in data flow diagrams, including ensuring unique names for processes and distinguishing inputs from outputs.

Balanced DFD

A data flow diagram where the number of inputs and outputs at one level matches those at its corresponding higher-level process.

How is a Data Store represented in a DFD?

An open ended rectangle.

What is a Data Store in DFD?

A symbol in a DFD representing a situation where a system retains data for future processes.

What is a Source/Sink in DFD

An external agent in a DFD representing the origin (source) or destination (sink) of data outside the system.

How is a Source/Sink represented in DFD?

Rectangle or Square

What is a Data Flow in DFD?

Arrows indicating the movement of data between symbols in a data flow diagram.

How is a Data flow represented in DFD?

Arrows, indicating the direction of data transfer.

What is a Process in DFD?

Work or action performed on data inside the system, transforms the data.

How is a process represented in DFD?

A process is represented by a circle or rounded rectangle in a data flow diagram, labeled with the name of the process.

Level-0 DFD

A high-level data flow diagram that shows a system’s major processes, data flows, and data stores.

Level-1 DFD

A detailed data flow diagram that shows the sub-processes of one of the processes in a Level-0 DFD.

Composite Data Flow

A data flow at one level that can be split into component data flows in subsequent levels without adding new data.

Steps for converting Use Case Diagram to DFD

Identify Main process
Identify Data flows
Identify External Entities
Generate Diagram