System Design By Kustanto

Process modeling (structured analysis and design) is an analysis and design technique that describes processes that transform inputs into outputs A process model is a formal way of representing how a business operates

What is system design???? System Design is to create a technical solution that satisfies the functional requirements for the system.

Tools Several tools used in the design of systems are: Data Flow Diagram, Data dictionary, Context diagram, Event list, Process spesification.

Data Flow Diagrams

Data Flow Diagram Data flow diagram shows business processes and the data that flows between them A diagram to show how data is captured, processed , stored and distributed within a system. This is generally represented during the analysis stage of a project, but can be further refined during the design stage to show more detail of how the system functions.

DFD Elements and symbol PROCESS Number An activity or function performed for a specific business reason This can be a computerised or manual transformation Name Every process has: Element A number (for identity process) A name function from process(verb phase and object) A description one or more output data flow Usually one or more input data flow Example: 1.1 Check patient status

DFD Elements and symbol DATA FLOW Name Illustrates the data flow from one process to anothe A single piece of data or a logical collection of data Always starts or ends at a process Element Every data flow has: A name (a noun) A description one or more connections to aprocess Example: Patient name

DATA STORE Every data store has: A collection of data that is stored in some way (database) Element Every data store has: D1 Name A number A name Example: D1 Patient

EXTERNAL ENTITY Every external entity has: A person, organization, or system that is external to the system but interacts with it Element Every external entity has: A name Example: Patient

Reading a DFD

Context Diagram First DFD in every business process Shows the context into which the business process fits Shows the overall business process as just one process (process 0) Shows all the external entities that receive information from or contribute information to the system

Level 0 Diagram Shows all the major processes that comprise the overall system – the internal components of process 0 Shows how the major processes are interrelated by data flows Shows external entities and the major processes with which they interact

Level 1 Diagrams Generally, one level 1 diagram is created for every major process on the level 0 diagram Shows all the internal processes that comprise a single process on the level 0 diagram Shows how information moves from and to each of these processes If a parent process is decomposed into, for example, three child processes, these three child processes wholly and completely make up the parent process

Level 2 Diagrams Shows all processes that comprise a single process on the level 1 diagram Shows how information moves from and to each of these processes Level 2 diagrams may not be needed for all level 1 processes Correctly numbering each process helps the user understand where the process fits into the overall system

Level 3/4 diagram IF it is necessary to produce a level 3 or level 4 diagram, the same steps would be followed as used when constructing the Level 1 diagram

Relationship Among DFD levels Context diagram Level 0 diagram Level 1 diagram Level 2 diagram

Example

Expert System DBD & Tifoid Context Diagram Data diseases, data symptom, data measuremnt of symptom, data rule, data login Data diseases, Data symptom Expert System DBD & Tifoid Expert (Doctor) Visitor /User Report data (diseases, sympton, measurement of symptom, rule patient) Data patient 2/16/2019

Level 0 DFD of export system DBD & Tifoid Expert System DBD & Tifoid Top level Level 0 1.0 Expert data 2.0 Diseases data 3.0 Symptom data 4.0 Rules data 5.0 Patient data 6.0 Report 2/16/2019

Level 0 DFD of export system DBD & Tifoid 1.0 Login & Password Username & passd D1 Username & password Diseases data Export (Doctor) D2 Diseases 2.0 Diseases data Symptom data D3 Symptom Measurement data D4 Measurement 3.0 Symptom data Rules data D5 Rules 4.0 Rules data Rules data D7 conclusion 6.0 Report detection of diseases Measurement data Visitor/ user Report the detection of diseases Symptom data Diseases data Patient data Patient data Entry Patient data 5.0 Patient data D6 Patient 2/16/2019

Do’s and Don’ts when constructing a Data Flow Diagram  

Do’s and Don’ts when constructing a Data Flow Diagram  

Do’s and Don’ts when constructing a Data Flow Diagram  

. Context or Level 0 Diagram example of how Data flow diagrams would be used to model the logic of data flows in a fast food burger bar. . Context or Level 0 Diagram Identify where data is captured from Identify where data is distributed to Describe the overall process Map these out in a diagram using the correct symbols Link them with data flows that are labelled

Level 0 Context diagram CUSTOMER

Identify where data is captured from Identify where data is distributed to Describe the overall process Map these out in a diagram using the correct symbols Link them with data flows that are labelled

Level 0 Context diagram KITCHEN CUSTOMER RESTAURANT MANAGER

Identify where data is captured from Identify where data is distributed to Describe the overall process Map these out in a diagram using the correct symbols Link them with data flows that are labelled

Level 0 Context diagram CUSTOMER KITCHEN Food ordering system RESTAURANT MANAGER

Identify where data is captured from Identify where data is distributed to Describe the overall process Map these out using the correct symbols Link them with data flows that are labelled

Level 0 Context diagram CUSTOMER KITCHEN Receipt Customer Order Receipt Customer Order Food Order Food ordering system Management Reports RESTAURANT MANAGER

Constructing a Level 1 diagram Identify and draw the processes that make up the Level 0 process Allocate descriptions to these Lay out the sources/sinks and data flows from the Level 0 diagram Draw in any data stores used in the process Link the new processes and data stores with named data links

Does this show enough detail? Level 0 Context diagram CUSTOMER KITCHEN Does this show enough detail? Customer Order Food ordering system Food Order Receipt Management Reports RESTAURANT MANAGER

Constructing a Level 1 diagram Identify and draw the processes that make up the Level 0 process Allocate descriptions to these Lay out the sources/sinks and data flows from the Level 0 diagram Draw in any data stores used in the process Link the new processes and data stores with named data links

Level 1 diagram These new processes may show a process which corresponds to actions such as : Capturing data from different sources Maintaining data stores Producing and distributing data to different

Receive and transform Customer Food Order 1.0 Receive and transform Customer Food Order

Level 1 diagram These may show a process which corresponds to actions such as : Capturing data from different sources Maintaining data stores Producing and distributing data to different

Receive and transform Customer Food Order 1.0 Receive and transform Customer Food Order 3.0 Update Goods Sold file 2.0 Update Inventory file

Level 1 diagram These may show a process which corresponds to actions such as : Capturing data from different sources Maintaining data stores Producing and distributing data to different

1.0 3.0 2.0 4.0 Receive and transform Customer Food Order Update Goods Sold file 2.0 Update Inventory file 4.0 Produce Management Reports

Constructing a Level 1 diagram Identify and draw the processes that make up the Level 0 process Allocate descriptions to these Lay out the sources/sinks and data flows from the Level 0 diagram Draw in any data stores used in the process Link the new processes and data stores with named data links

1.0 3.0 2.0 4.0 CUSTOMER Customer Order Receipt KITCHEN Food Order Receive and transform Customer Food Order 3.0 Update Goods Sold file 2.0 Update Inventory file 4.0 Produce Management Reports RESTAURANT MANAGER Management Reports

Constructing a Level 1 diagram Identify and draw the processes that make up the Level 0 process Allocate descriptions to these Lay out the sources/sinks and data flows from the Level 0 diagram Draw in any data stores used in the process Link the new processes and data stores with named data links

CUSTOMER KITCHEN 1.0 Receive and transform Customer Food Order Customer Order Food Order Receipt 3.0 Update Goods Sold file 2.0 Update Inventory file D2 Inventory File Goods Sold File D1 4.0 Produce Management Reports RESTAURANT MANAGER Management Reports

Constructing a Level 1 diagram Identify and draw the processes that make up the Level 0 process Allocate descriptions to these Lay out the sources/sinks and data flows from the Level 0 diagram Draw in any data stores used in the process Link the new processes and data stores with named data links

CUSTOMER KITCHEN 1.0 Receive and transform Customer Food Order Customer Order Food Order Receipt Goods Sold Inventory Data 3.0 Update Goods Sold file 2.0 Update Inventory file Inventory Data Goods Sold Data D2 Inventory File Goods Sold File D1 4.0 Produce Management Reports Daily Inventory Depletion Amounts Daily Goods Sold Amount RESTAURANT MANAGER Management Reports

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