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This content is an extract from GetAhead in Business Analysis - the FULL course is in eBook and multimedia CD-Rom format.
Example Context Diagram.
The components of a context diagram are clearly shown on this page. The system
under investigation is represented as a single process, connected to external
entities by data flows and resource flows. The context diagram clearly shows the
interfaces between the system under investigation and the external entities with
which it communicates. Therefore, whilst it is often conceptually trivial, a
context diagram serves to focus attention on the system boundary and can help in
clarifying the precise scope of the analysis.
Library Context Diagram.
The context diagram shown on this screen represents a book lending library. The
library receives details of books, and orders books from one or more book
suppliers. Books may be reserved and borrowed by members of the public, who are
required to give a borrower number. The library will notify borrowers when a
reserved book becomes available or when a borrowed book becomes overdue. In
addition to supplying books, a book supplier will furnish details of specific
books in response to enquiries. Note, that
communications involving external entities are only included where they involve
the 'system' process. Whilst a book supplier would communicate with various
agencies, for example, publishers and other suppliers - these data flow are
remote from the 'system' process and so this is not represented on the context
diagram.
Stepwise Diagram Evolution.
Firstly, draw and name a single process box that represents the entire system.
Only when you have drawn your version should you go to the next page, to see a
suggested solution.
Next, identify and add the external entities that communicate directly with the
process box. Do this by considering origin and destination of the resource flows
and data flows.
Finally, add the resource flows and data flows to the diagram.
In drawing the context diagram you should only be concerned with the most
important information flows. These will be associated with how orders are
received and checked, with providing good customer service and with the paying
of invoices. Remember that no business process diagram is the definitive
solution; there is no absolute right or wrong.
The shop manager and staff do not appear as entities at this level; as both
occur within the system process box. Several points could be debated. For
example, should the resource flow 'Product' be two way in both cases, allowing
the return of faulty goods? You will need to make numerous decisions like this
as you develop a business model.
This content is an extract from GetAhead in Business Analysis - the FULL course is in eBook and multimedia CD-Rom format. TOP
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