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External Entity descriptions
In the current physical, External Entities are
used to show sources and recipients of data from the business system
under investigation. They can represent:
- People
- Organisations
- Other business systems
- Computer systems
At this stage, the operational staff are
considered to be part of the processes so they tend not to be shown.
As usual, though, bend the rules if it helps with
communication and show any that are sources / recipients of 'important'
flows of data, e.g. a manager providing authorisation or a user
triggering a process.
The External Entities listed in the table below
all come
from the top level DFD. It's possible that more will be discovered as
the DFD is decomposed into lower levels.
| Name |
Description |
| Accounts |
The
accounts department. They do all the invoicing, debt chasing, credit
checking and financial reporting.
|
| Courier |
Items
are usually delivered to customers via a courier service. The present
service is provided by Alacrity Courier Services
|
| Customer |
Customers
are retail outlets, concessions and mail order firms. Acme Fashion
Supplies doesn't sell to individuals. |
| Marketing
Department |
The
marketing department introduce new products and decide on those to be
withdrawn. They also do mailshots to customers. |
| Supplier |
Acme
Fashion Supplies buys products from suppliers. They are delivered by a
variety of methods, sometimes courier, sometimes by suppliers' own
delivery vans. Their are four major suppliers and a number who supply niche items. |
| Travelling Sales Team |
Acme
Fashion Supplies have a small travelling sales team. As part of this they
bring or phone in orders. |
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