IntroductionIntroduction

Process ModelingProcess Modelingwithwith

Data Flow Diagrams (DFD)Data Flow Diagrams (DFD)

What is a Business Process?What is a Business Process? A network of activities, resources, A network of activities, resources,

facilities, and information that interacts facilities, and information that interacts to achieve some business functionto achieve some business function11

1 Inventory Mgmt Process, Experiencing MIS, Kroenke, Pearson Prentice Hall, 2008, Chpt 2

Why Model a Business Why Model a Business Process?Process?

Description / Explanation (e.g. to Description / Explanation (e.g. to a new hire you are training)a new hire you are training)

Prescription (e.g. to your boss for Prescription (e.g. to your boss for how it can be improved)how it can be improved)

Sample Graphical Tools for Sample Graphical Tools for Modeling OrganizationsModeling Organizations

PEOPLE:PEOPLE: Organization Chart (a.k.a. "Org Organization Chart (a.k.a. "Org Chart") Chart") – hierarchal people modelhierarchal people model

– shows who reports to whomshows who reports to whom

DATA:DATA: Entity Relationship Diagram (a.k.a. Entity Relationship Diagram (a.k.a. "ERD"): "ERD"): – data only model data only model

– no people, hardware, flows or processes no people, hardware, flows or processes

PROCESS:PROCESS: Data Flow Diagram (a.k.a. "DFD") Data Flow Diagram (a.k.a. "DFD")– activities, people, hardware, & data model. activities, people, hardware, & data model.

– the focus for this part of BSAD 141!the focus for this part of BSAD 141!

Terminology for DFD Process ModelingTerminology for DFD Process Modeling 2 Types of “Entities”: Person, place, or thing (e.g. computers) 2 Types of “Entities”: Person, place, or thing (e.g. computers)

– ExternalExternal: any entity that does not perform any information processing activities : any entity that does not perform any information processing activities – InternalInternal: an entity that performs at least one information processing activity : an entity that performs at least one information processing activity

2 Types of “Activity”: an action being performed by an internal or 2 Types of “Activity”: an action being performed by an internal or external entity. external entity. – Information processing (Information processing (DPDP) actions: ) actions:

• transform data transform data • retrieve data from storage retrieve data from storage • filing data filing data • document processing document processing • data entry data entry • verification verification • classification classification • arrangement or sorting arrangement or sorting • calculating calculating • summarizing summarizing

– NOT information processing (NOT information processing (NDPNDP) actions: ) actions: • Sending & receiving data between entities are NOT information processing Sending & receiving data between entities are NOT information processing

actions. actions. • Operational & physical business activities are NOT information processing: Operational & physical business activities are NOT information processing:

e.g. picking or packing a sales order, inspecting goods at receiving dock, or e.g. picking or packing a sales order, inspecting goods at receiving dock, or counting cash. counting cash.

What is a Data Flow Diagram (DFD)What is a Data Flow Diagram (DFD)

A graphical representation of a A graphical representation of a business system or subsystem that business system or subsystem that shows how system components shows how system components (entities, activities and data) are (entities, activities and data) are interconnected.interconnected.

More DFD TerminologyMore DFD Terminology Business ProcessBusiness Process

– An activity that converts inputsAn activity that converts inputs intointo outputsoutputs

– VerbsVerbs rather than Nouns rather than Nouns

– Types: DP vs NDPTypes: DP vs NDP

Data FlowData Flow– Data moving from one place to another without being transformed Data moving from one place to another without being transformed

– a.k.a. pathway for dataa.k.a. pathway for data

Data StoreData Store– A data flow at restA data flow at rest

External EntityExternal Entity – An object that either sends or receives flows from within the system An object that either sends or receives flows from within the system

(a.k.a. focus area) but doesn’t perform any processing activities of (a.k.a. focus area) but doesn’t perform any processing activities of interestinterest

– a.k.a. terminator, source, or sinka.k.a. terminator, source, or sink

DFD Symbol SetsDFD Symbol Sets

ProcessProcess

Data FlowData Flow

External External

EntityEntity

Data StoreData Store

Customer

Completed Orders

or

or Completed Orders

orCustomer

Yourdon-DeMarco Gane-Sarson

1.0

Enter Report

Parameters

1.0

EnterReport

ParametersProject

ManagersCustomer Order

Customer Order

Two Types of DFDsTwo Types of DFDsContext DiagramContext Diagram: :

– A graphical, top-level (i.e. overview) representation of A graphical, top-level (i.e. overview) representation of the data flows the data flows into and out of a single system under study.into and out of a single system under study.

– Marks the “boundary” (scope) of theMarks the “boundary” (scope) of the sub-system under study (a.k.a. sub-system under study (a.k.a. focus area). focus area).

– Often exploded into more detail.Often exploded into more detail.

– Context ExampleContext Example: :

Logical or Physical Data Flow DiagramLogical or Physical Data Flow Diagram: : – A detailed graphical representation of the data flows, processes, stores, A detailed graphical representation of the data flows, processes, stores,

and sources/destinations in a business sub-system.and sources/destinations in a business sub-system. – Used to model:Used to model:

• How “processes” transform input data flows into output data flowsHow “processes” transform input data flows into output data flows

• How “data” move through an information systemHow “data” move through an information system

– Logical DFD Example Logical DFD Example / / Physical DFD examplePhysical DFD example

– Processes are often systematically (hierarchically) broken down into even Processes are often systematically (hierarchically) broken down into even more detailed DFDmore detailed DFD..

Hierarchical Arrangement of DFDsHierarchical Arrangement of DFDs

ContextDiagram

Level 1Diagram

Level 1.1Diagram

Level 2.1Diagram

Level 3.1Diagram

Level 3.1.1Diagram

Level 3.1.2Diagram

Decomposition:At each level, the processesand data flows becomemore detailed / descriptive

“Primitive” DFDs

Balanced: External Flows match at each

level

QUESTIONSQUESTIONS

?

10 minute Quiz