Data Flow Diagram for System Analysis and Design

Running head: Data Flow diagram 1
Data Flow Diagram
Name of the Student:
Name of the Institution:

Data Flow diagram 2
System Analysis
What is the purpose of DFD and how is it related to the concept of scope and boundary
conditions?
A data flow diagram refers to a traditional tool used to visually and
graphically/diagrammatically represent flow of information within a system, and between the
different interacting units and actors as defined by the system (Visual Paradigm, 2012). It is a
model perspective of a system that uses graphical representation tools to make users understand
how information flows through the system, and the activities that trigger processing of such
information.
The purpose of this model is to enable the project team, clients and expected system users
to effectively work together during the analysis and requirements specification and elicitation
phases of software development.
Software engineers use Data flow Diagrams to represent processes, data flows, and
external entities and data stores. Processes consists of all activities that are carried out by system,
and through which information is used and equally transformed. Data-flows refers to the inputs
and associated/ corresponding outputs from these processes, while external entities are denoted
using ovals and represent sources of information and its recipients and data stores show where
this information is stored after complete execution/processing.
By defining and representing system requirements and info flow graphically, software
engineers depict scope and system boundaries as a whole. This is achieved by defining and
representing all system activities, and what each actor/entity is capable of doing within the
system and showing results of such executions.

Data Flow diagram 3
Mortgage broker
For the mortgage broker system DFD, the broker could be represented as a set of multiple
processes since they only creates outputs rather than inputs to the system. In this business
scenario, the mortgage broker acts as an intermediary between a loaning firm’s system and a
clients. The primary source of information is the business offering the service and the customer
requesting for the mortgage, and hence they (mortgage brokers) will be represented using
multiple processes through which they interact with the customer and the business, presenting
customer requests to the system, and outputs of such requests to the customer. These processes
are therefore represented as a series of sequential processes.
Constructing a logical DFD
A physical Data Flow Diagram represents the actors performing respective actions. In the
shopping data flow diagram provided, the customer is represented as an external entity that
performs two processes in a linear sequence. To the contrary, a logical Data Flow Diagram
references to the customer- who is performing the actions by explicitly representing the Stock
list- which in this case is the data store, rather than within the logic of Select groceries process.
Furthermore, processes in the physical data flow diagram are now represented in parallel due to
the fact that logical representation separates the physical groceries from their respective
information content.