Data Flow Diagrams
Student Philosophy Club
Business Philosophy Club
• Business Philosophy Club (BPC) is a
student group at Oakland University.
• The club exists to talk about the
philosophical foundations of business,
listen to guest speakers and become
better, more aware business people.
• The club meets regularly and issues an
annual report to its advisors and sponsors,
who are OU professors.
System Goals
• The BPC would like to systematize their
activities.
• The goals of the BPC include maintaining
membership, having good meetings, and
providing advisors and sponsors with
reports.
Decomposition of Goals
BPC Goals
Maintain
Membership
Run Good
Meetings
Provide Valid
Reports
Subsub Subsub Subsub Subsub Subsub Subsub Subsub Subsub Subsub
Goal
Goal
Goal
Goal
Goal
Goal
Goal
Goal
Goal
1.1
1.2
1.3
2.1
2.2
2.3
3.1
3.2
3.3
All systems, especially information systems, have goals. These
goals can be “decomposed” or broken down into subgoals and the
subgoals further broken down into subsubgoals, etc.
Goals into Processes
• Each goal corresponds to an information
process:
 Maintaining membership requires a process
to handle members and their information
 Having good meetings requires a process to
schedule and report on meetings
 Good reporting needs a process to
accumulate the information needed for the
annual and ad hoc reports
Decomposition and Processes
System
Process 1:
Handle
Membership
Process 2:
Run Good
Meetings
Process 3:
Provide Valid
Reports
Process Process Process Process Process Process Process Process Process
1.1
1.2
1.3
2.1
2.2
2.3
3.1
3.2
3.3
Goals are associated with processes. The “success” of each
process means reaching the associated goal. In turn, that means
that each process’s success depends on success of subprocesses.
Data Flow Diagram: Basic
Elements
“Member
Name” for
example
1.0 or
3.4.2, for
example
Data Flow Name
Data Flow
Eg.
“Register
New
Member”
Process
Name
Identifier
Identifier
“A” for
example
Process Box
Data Store
Name
Data Store
“Member
List” for
example
“p” for
example
Identifier
Actor
Name
External Actor
“Applicant”
for
example
Membership Process
• Business Philosophy Club (BPC) is a student
group. It is open only to students at Oakland
University in their third or fourth years who have
major status in the SBA. Members pay a $10
registration fee. There are no other costs (such
as annual membership). There are no other
membership hurdles.
• The application process consists of two
subprocesses: An initial application query to
determine eligibility and a process to handle the
registration payment.
Data Flow Diagram: Basic
Structures
Applicant Eligibility Process
Applicant
1.1
Applicant
Questions
Determine
Eligibility
Preliminary
Applicant
Decision
Valid Application
Applicants
A
a
ApplicantInfo
Data Flow Diagram: Basic
Structures
Applicant Approval Process
a
ApplicantPayment
1.2
Applicant
Approve
Application
Applicant
Members’p
Approval
Application Info
A
Applicants
Applicant
Approval Data
The Improvement Goal
• Some of the current processes are
inefficient.
• Some may be problematic in that the
information used or generated is wrong or
misleading and may lead to poor
decisions.
• Some of the processes are inefficient or
may be useless!
Data Flow Diagram:
Basic Laws 1
Law of Conservation of
Information
Incoming Data Flow 1
Xx.yy
Resulting Data Flow
Incoming Data Flow 2
Process
Incoming Data Flow 3
Information cannot come from nowhere. The result
of any process must be traceable to the sum of the
data flows entering the process.
BPC Meetings
• Meetings are held about monthly, although
the schedule isn’t rigidly fixed because the
membership is so busy.
• Members like to meet at the OC, but
sometimes their favorite rooms aren’t
available, nor are the members and the
officers.
• In the past, rooms to large or too small or
incompatible with desired use were
reserved
Data Flow Diagram:
Basic Laws 1 (Example)
Law of Conservation of
Information
Attendee Information
2.1
Scheduled Meeting
Information
Venue Information
Schedule
Meeting
Meeting properties
The next meeting depends on the availability of the
attendees, the availability of the room, and the type
of meeting to be scheduled such as whether this is
a philosophical debate or business meeting
Data Flow Diagram:
Basic Laws 2
Law of Utilization of
Information
Incoming Data Flow 1
PP.qq
Resulting Data Flow
Incoming Data Flow 2
Process
Incoming Data Flow 3
Information cannot go nowhere. The result of any
process must depend on ALL of the data flows
entering the process.
Meeting Minutes
• To aid organizational memory, the minutes
of each meeting are written up by the BPC
scribe.
• These minutes are based on notes that
the scribe takes.
• Sometimes the chair of the meeting
“corrects” the minutes with his or her own
comments.
Data Flow Diagram:
Basic Laws 2 (Example)
Law of Utilization of
Information
Meeting Notes
2.3
Meeting Minutes
Schedule Information
Create
Minutes
Chairperson Wishes
The minutes of a meeting depend only on the notes
taken at the meeting and additional information
about scheduling, NOT what the chairperson
wished had happened at the meeting
Data Flow Diagram:
Basic Laws 3
Law of Logical Data Flow
Incoming Data Flow 1
AA.bb
Resulting Data Flow
Incoming Data Flow 2
Process
Incoming Data Flow 3
Information flows reflect logical dependency.
Results of processes reflect a logical
transformation of all of the inputs.
Reporting
• An annual report of the meetings and
finances is produced each year for the
advisors and sponsors.
• In the past, the annual report was able to
include audited financial statements, but
because of various circumstances, the
annual report has had to be produced
early.
Data Flow Diagram:
Basic Laws 3 (Example)
Law of Logical Data Flow
Meeting Minutes
3.4
Annual Report
Chairperson Wishes
Next Year’s Audited
Statements
Create
Annual
Report
The annual report cannot include a set of financial
statements not available at the time the report is
due.
Data Flow Diagram:
Basic Laws 4
Law of Data Integrity
AA.bb
Resulting Data Flow
Incoming Data Flow 1
Process
A
Data Store
Access to information across the system boundary
must be through a system process. Direct access
to data bases is not (generally) allowed.
Ad-Hoc Reporting
• Sponsors and advisors are really keen to
know about meetings and sometimes they
come into the office and look at the reports
before they are generated.
• This has led to misunderstanding,
especially if unapproved minutes based on
poorly-taken notes are read.
Data Flow Diagram:
Basic Laws 4 (Example)
Law of Data Integrity
3.1
Ad Hoc Report
Ad HocReport Request
Advisor
Inform
Advisor
Advisor
A
Data Store
Access to information across the system boundary
must be through a system process. Direct access
to data bases is not (generally) allowed.
The Whole Shebang
0
Student Philosophy Club Information System
Members
1.0
2.0
3.0
Handle
Members’p
Hold
Meetings
Produce
Reports
Sponsors
Advisors
Applicants
A M’Ship
B Meetings
C Reports