18
Figure 2. 10
External Agent
(Source: Whitten, Jeffry L.,
Bentley, Lonnie D.,
and Dittman, Kevin C. 2000. System Analysis and Design
Methods)
2.1.4.3 Which is legal and illegal in DFD?
Based Figure above, there are 4 legal how to construct DFD such as:
1. Input from one external agent to another external agent through process, in which
a
process is needed to exchange data between 2 external agents.
2. Input
from an external agents to data store through process,
in which a process
is
needed to update (or use) a data store.
3. Input
from data store to an external agents
through process.
This
happens
when a
process is needed to present data from a data store.
4. Input from one data store to another data store through process, where a process is
needed to move data from one data store to another data store.
 |