What is the Difference Between DFD and Flowchart? with Proper Definition and Brief Explanation

The main difference between DFD and Flowchart is that DFD is a graphical diagram that represents the data flow of a system while flowchart is a graphical diagram that represents the sequence of steps to solve a problem.

Software development is a complex process and it is difficult to write the whole system program directly. Therefore, it is necessary to model the system to gain an understanding and then program the modules. There are several diagrams that help model the system. DFD and flowchart are two of them. DFD illustrates the inputs, outputs, how the data flows through the system, and where the data will be stored. On the other hand, a flowchart helps to illustrate the steps to solve the problem. It can be used as a basis for writing the program.

Key Areas Covered

1. What is DFD?
     – Definition, Functionality
2. What is a flowchart?
     – Definition, Functionality
3. What is the difference between DFD and Flowchart?
     – Key Differences Comparison

Key terms

Data Flow Diagram or DFD, Flowchart

What is DFD?

DFD stands for Data Flow Diagram . It represents how a system processes data and describes where the data comes from, where it goes, and how the data is stored. DFD became popular during the year 1970. There are two types of notations for DFD. They are Yourdon and Coad, Gane and Sarson.

Youdon and Coad – These types of diagrams are used for system analysis and design. The circles represent the processes.

Earn and sarson – These types of diagrams are used for information systems. Squares with rounded corners represent the processes.

Some common DFD notations are as follows:

Process – Transforms the incoming data stream into the outgoing data stream.

Data Warehouse – Represents the data repositories in the system.

Data Flows – Represents the data flow path.

External Entities – Represents objects outside the system. The system communicates with these external entities. They are the sources and destinations of the inputs and outputs of the system.

Also, DFD diagrams have layers or levels to organize the data. The context diagram is the top level. Generalizes the functionality of the entire system and the relationship with external entities. The level 1 diagram provides more detail than the context diagram. However, level 2 diagrams provide more detail than level 1, and level 3 diagrams provide more detail than level 2 diagrams. Also, you need to break down the processes down to the pseudo code, which is a human-readable structure. by humans to understand the program.

What is a flowchart?

A flowchart is a diagram that helps represent an algorithm. In other words, a flowchart helps to write an algorithm.

Algorithm

In computing, an algorithm is a step-by-step procedure to solve a given problem. If the problem is complex, it is possible to divide the problem into multiple sub-problems and solve each of them to solve the main problem.

An algorithm to find the area of ​​the rectangle is as follows.

  1. Initialize area = 0
  2. Enter the length and width
  3. Multiply them and store the result in area.
  4. Printing area.

The flowchart to calculate the area is as follows:

                                                               Figure 1: A flowchart 

Therefore, a flowchart is a graphical representation of writing an algorithm. In addition, the flowchart symbol notations are as follows.

Oval – Represents the beginning and the end.

Diamond – Represents input and output operations (inputs can be user input, while outputs are the results displayed on the screen)

Rectangle – Represents a process. E.g. – Initialization of variables, calculations.

Diamond symbol – Used for decision making

Circle (small) – It is connectors

Arrow – Represent the sequence of steps.

Difference Between DFD and Flowchart

Definition

DFD is a graphical representation of the flow of data through an information system, which models its process aspects. In contrast, a flowchart is a schematic representation that illustrates a solution model for a given problem. Thus, this explains the basic difference between DFD and flowchart.

Applicability

DFD can be used for complex systems. Although a flowchart is not very suitable for a complex system, it is applicable for small to medium programs. Hence, this is another difference between DFD and flowchart.

Use

Also, Its Usage Attributes Another difference between DFD and flowchart is its usage. DFDs help understand the system overview without going into more detail, while flowcharts help analyze, design, and manage a program.

Conclusion

In short, DFD and Flowchart are two types of diagrams that help to develop software. The main difference between DFD and Flowchart is that DFD is a graphical diagram that represents the data flow of a system whereas a flowchart is a graphical diagram that represents the sequence of steps to solve a problem.

Reference:

1. What is the DFD? Data Flow Diagram, Symbols and More, SmartDraw, September 7, 2018, Available here.
2. “Data Flow Diagram.” Wikipedia, Wikimedia Foundation, October 30, 2018, Available here.
3. “Flow chart”. Wikipedia, Wikimedia Foundation, October 18, 2018, Available here.

Courtesy image:

1. “Backup-DFD” By Sukari at English Wikipedia – Created By Sukari at English Wikipedia (Public Domain) via Commons Wikimedia

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