Transcript No Slide Title

Biznesa procesu un datu
plūsmas diagrammas
(turpinājums)
Information Systems and
Business Processes
Business process
Information
system
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B.Wangle/ 7/16/2015
Workflow system
2
The “Drain Pipe Syndrom”
Business Process
IS-1
IS-2
IS-3
IS-4
IS-5
Specific systems for each
business function.
Little integration.
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B.Wangle/ 7/16/2015
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Janis Tenteris
Context
Leveled diagram
0
Top
1
2
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Kendall, Kendall, 1995, P 234
Context level diagram
External
Entity
1
Input A
System
Name
External
Entity
2
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Input B
Output C
External
Entity
3
5
Kendall, Kendall, 1995, P 234
External
Entity
1
External
Entity
2
External
Entity
1
Input A
Input B
Context level diagram
Input A
1
General
Process
AAA
Record A
Data flow B
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Input B
Output C
External
Entity
3
Record E
D2 Data Store 2
Record A
3
General
Process
CCC
2
General
Process
BBB
Data flow C
D1 Data Store 1
External
Entity
2
External
Entity
3
Output C
System
Name
Record E
Data flow D
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General
Process
DDD
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Top or 0 level diagram
Kendall, Kendall, 1995, P 233
Developing DFD
Using Top-Down Approach
•
Make a list of business activities and use it to determine various
–
–
–
–
•
•
•
•
•
•
External Entities
Data Flows
Processes
Data Stores
Create a context diagram which shows external entities and data flows to and
from the system. Do not show any detailed processes or data stores
Draw diagram 0, the next level. Show processes, but keep them general. Show
data stores at this level
Create a child diagram for each of the processes in Diagram 0
Check for errors and make sure the labels you assign to each process and data
flow are meaningful
Develop a physical data flow diagram from the logical data flow diagram.
Distinguish between manual and automated processes, describe actual files and
reports by name, and add controls to indicate when processes are complete or
errors occur
Partition the physical data flow diagram by separating or grouping parts of the
diagram in order to facilitate programming and implementation
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Kendall, Kendall, 1995, P 234
Free choice of the starting point and
working forward/backward from the point
•
Start with the data flow from an external entity on the input side, ask questions
such as:
–
–
–
•
Work backwards from an output data flow. Examine the output fields. For each
field on the output ask:
–
–
•
Where does it come from?
Is it calculated or stored on a file?
Examine the data flow to or from a data store. Ask:
–
–
•
What happens to the data entering the system?
Is it stored?
Is it input to several processes
What processes put data into the store
What processes use the data (Note, that data store may be produced by a different
system - there may not be any data flow into the data store)
Analyse a well defined process. Look at what input data the process needs and
what output produces, Then connect the input and output to the appropriate data
stores and external entities
• Take note of any fuzzy areas where you are unsure of what should be included,
or what input or output is required. Awareness of problem areas will help to
formulate a list of questions for follow-up interviews with key users
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Logical checklist for DFD
1. Have you got a process behaving as a sink or source (external entity) ?
Produce
labels
Customer name range
WRONG!!
Labels
Produce
labels
Labels
RIGHT
Customers
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Logical checklist for DFD
2. For a given process, have you got enough (or too many) inputs to
produce the stated output?
Estimate
delivery
date
Customer order
Customer order
Estimate
delivery
date
Dated order
WRONG !!
Dated order
RIGHT
Delivery Schedule
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WRONG !!
2
1
3
Data flows should not
split into two or more
different flows
All data flows must either
originate or terminate at a
process
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Business level DFD and DFD for database
BM
Be careful to do not
loose relationships
between the levels!!!
ISM
MK,7/16/2015
96
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BM
Articles
P1.2
calculate
price
P1.1
line
item
P1.4
amount
customer
item list
receipt
Cashier
P1.3
ready
calculate
sum
Print
customer
line tot.
Sales
MK,7/16/2015
96
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ISM
Articles
P1.2
calculate
price
line
item
amount
customer
P1.3
ready
customer
calculate
sum
line tot.
Sales
MK,7/16/2015
96
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Types of data flow diagrams
• Physical
– includes details HOW the system works by physical items and
physical processes
– state the person performing the processing
• Logical
– contains only details of WHAT is achieved with no reference to
anything physical
Physical
Logical
BM
ISM
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Logical
Physical
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Addapted from I.T. Hawryckiewycz Introduction to Systems Analysis and Design, Prentice Hall, 1991
Convertion to logical DFD
• remove all the processes that refer to physical
activities and do not transform information
• expand the remaining processes to the logical
functions
– take each process
– find out what it does
– replace by a leveled DFD of logical functions
• combine expansions into a lower level logical DFD
• combine any similar or common functions and
represent the combinations as processes in higher
level logical DFD
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Addapted from I.T. Hawryckiewycz Introduction to Systems Analysis and Design, Prentice Hall, 1991
Top-level physical DFD
Checked
order
Unaccepted
order
Customers
Order
1
Reception (clerk)
Unable to meet
deadline
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2
Sort into areas
Stored
orders
3
Send to production
section
4
Production
Dispatched
orders
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Addapted from I.T. Hawryckiewycz Introduction to Systems Analysis and Design, Prentice Hall, 1991
Expanded processes
Unaccepted
order
Customers
Order
ORDERS
1.1
Record order
Unable to meet
deadline
Received
order
1.2
Check type
of order
4.1
Check available
resources
Accepted order
4.2
Commit resources
to production
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Checked
order
RESOURCES SCHEDULES
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Addapted from I.T. Hawryckiewycz Introduction to Systems Analysis and Design, Prentice Hall, 1991
Recombined logical processes
Replay to
order
Customers
Order
1
Record order
ORDERS
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Received
order
2
Check production
feasibility
Accepted
order
3
Commit resources
to production
RESOURCES SCHEDULES
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Kendall, Kendall, 1995, P 241
Features of logical and physical DFD
Design Features
Logical
Physical
What the model
depicts
How the business
operates
How the system will be implemented (or
how the current system operates)
What the processes Business activities
represent
Programs, program modules and manual
procedures
What the data
stores represent
Physical files and databases, manual files
Collections of data,
regardless of how
the data is stored
Type of data stores Show data stores
representing
permanent data
collections
System controls
Show business
controls
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Master files, transaction files,. Any
processes that operate at two different
times must be connected by a data store
Show controls for validating input data,
for obtaining a record (record found
status), for ensuring succesful
completition of a process and for systems
security (example: journal records)
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Kendall, Kendall, 1995, P 244
Contents of Physical Data Flow Diagrams
• Manual processes
• Processes for adding, deleting, changing, and updating
processes
• Data entry and verifying processes
• Validation processes for ensuring accurate data input
• Sequencing processes to rearrange the order of records
• Processes to produce every unique system output
• Immediate data stores
• Actual file names used to store data
• Controls to signify completition of tasks or error conditions
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Current System
DFD may describe the current system
as well as the proposed one
Proposed System
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Business process diagrams (BPD)
and DFD
BPD
Ir līdzīga
Physical
Logical
BM
ISM
Logical
Physical
MK, 96
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Business process diagrams (BPD)
and DFD
• Datu plūsmas diagramma tiek zīmēta augstākā abstrakcijas
līmenī nekā biznesa procesa diagramma
• Salīdzinājumā ar BPD, datu plūsmas diagrammā neattēlo:
– Procesa izpildītāju
– Trigera nosacījumus
– Zarošanās nosacījumu saturu
• Biznesa procesa diagrammā avoti un izlietnes var būt procesi –
datu plūsmu diagrammās tie parasti ir objekti
• Galvenais, kas jāparāda datu plūsmas diagrammā – kā dati
plūst caur procesiem
• Galvenais, kas jāparāda biznesa procesa diagrammā – ar
kādiem paņēmieniem (piemēram, darbību secību) dotajā
kontekstā tiek sasniegts biznesa procesa mērķis
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BPD fragments
DPD fragments
Answer
Applicant
Regularly
Prepare Application
Applicant
Application Form
Application
Form
Deliver and Register Application
Applicant AND Administrator
Registered Appl
Form
Every
Morning
Deliver and
Register Application
Registered Application Form
Discuss in Membership Committee
Registered Appl Form & Every Morning
Management
UNIFORM("10m","50m")
Not
Acceptable
40 %
Discuss in
Membership
Committee
Acceptable
60 %
Decision
Approved
Application
Decision
Decision
Send Answer
Administrator
NORMAL("15m","5m")
Tag: Negative
Send answer
Send Answer
Administrator
NORMAL("15m","5m")
Tag: Positive
Answer
Answer
Add
ReceiveAnswer
Applicant
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BPD fragments
DPD fragments
Answer
Applicant
Regularly
Prepare Application
Applicant
Application Form
Application
Form
Deliver and Register Application
Applicant AND Administrator
Trigera nosacījums
Registered Appl
Form
Every
Morning
Deliver and
Register Application
Registered Application Form
Discuss in Membership Committee
Registered Appl Form & Every Morning
Management
UNIFORM("10m","50m")
Not
Acceptable
40 %
Discuss in
Membership
Committee
Acceptable
60 %
Decision
Approved
Application
Decision
Decision
Send Answer
Administrator
NORMAL("15m","5m")
Tag: Negative
Administrator
NORMAL("15m","5m")
Tag: Positive
Answer
Answer
ReceiveAnswer
Applicant
7/16/2015
Send answer
Send Answer
Add
Ja šie procesi
būtu dažādi, tad
DPD būtu divi
nevis viens
process
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