Persons (or groups of persons)
Places
Objects
Events (about which data is captured)
Concepts (about which data
is
important)
Data stores depicted on a DFD store all instances of data entities (depicted
on an ERD)
Figure 2. 9 Data Store
(Source: Whitten, Jeffry L.,
Be ntley, Lonnie D., and Dittman, Kevin C.
2000. System Analysis and Design
Methods)
3. External
Agent.
An
external
agent
defines
a
person,
organization
unit,
or
other
organization that lays outside of the scope of the project but that interacts with the
system being studied.
External
agents
define
the
“boundary”
or
scope
of
a
system
being
modeled.
As scope changes, external agents can become processes, and vice versa.
Almost always one of the following:
Office, department, division
inside
the business but outside
the
system scope.
An external organization or agency.
Another business or another information system.
One of your system’s end- users or managers
(
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