Introduction to Data Flow Diagrams
A data flow diagram is a graphical representation of data of a system that provides information as output with the given input and the flow process. A data flow diagram can be physical or logical. The physical one defines the entire implementation of data and the logical one defines the data flow to perform some actions. A data flow diagram is basically denoted by using numerical symbols like circles, arrows, rectangles to categorize input data, output result, and the directions through which data is flowing in the entire process structure.
Why Data Flow diagram is need?
It is actually the diagrammatic representation of the flow of data that is associated mainly with the process and functions of data items that store, modify, update and manipulate data between different environments and the various components of the program. Due to its representation in a diagrammatic way, it is very easy to comprehend information between the end-user and the program designer. The entire structure of the data flow diagram starts from the brief summary of data and expands it to detailing each program that is to be stored and executed. Therefore, the entire process of a data flow is required because of a few reasons.
- The diagram represents the logical flow of the information of the system.
- The diagram helps in the requirement of constructing physical elements for the system.
- The diagram also helps in denoting the overall flow of data with the help of easy and sophisticated numerical symbols that are easy to understand.
- It helps in the connection between the requirements of the system that are connected both manually and also automated.
How Data Flow Diagrams work
It is a data representation process that can be categorized into the following levels and steps. The levels are numbered as Level 0, Level 1, Level 2, Level 3, and beyond.
Level 0 Data flow diagram denotes the overview of the entire process that is analyzed and prototyped. The single bubble represents the software requirements and the inward and outward arrows denote the input data and output data respectively. It is further broken down into a high level of processes that convey detailed information regarding data. It is basically a context diagram and the entire process is repeated until the requirements are better understood and solved. In between the levels, it is very wise to preserve the input and output data.
Level 1 It represents a better and well explained detailing of broken diagrams from Level 0 Data flow diagram. So, basically, this level is further subdivided into multiple bubble diagrams or processes that carry more information about the system. The main objectives or functions are highlighted through this level when the high-level process of the level 0 context diagram is further subdivided into multiple processes. In this level, lots of input arrows are required to form the diagram that contains multiple output flows of data.
Level 2 It is the next step of the Level 0 Data flow diagram that creeps slowly and deeply into the main functioning of the system. The processes again go deeper and then record each functionality and features of the system. This level acts as the linking of data between entities and helps in extracting the entities and the processes into the separate flow of information as diagrams.
Level 3 Beyond is also possible but rare as it results in more complexity in communicating or modeling the system functionalities as per the requirements provided.
Notation of Data Flow Diagrams
The notations in data flow diagrams play a valuable role as it helps in determining the entire visual representation of data flow that helps in gathering, analyzing, visualizing, and executing the information provided from external systems. The symbols are of different shapes and sizes are made unique to provide efficient communication and collaboration. There are basically four components to describe the symbols or notation of a data flow diagram.
External entity notation: This symbol helps in representing the data flow among external systems, source, and destination of the system data. In terms of business purpose, this notation determines the data that flows in and goes out of the system. The external entities are drawn over the edges of the diagram.
Process notation: It is represented using bubbles where the entire functionality of the business process is handled and information is subdivided into further levels. The notation denotes how data is flowing through a particular process.
Datastore notation: This notation represents a collection of data items to be stored in the system. The data that is required, or will require to be in the processing are stored here.
Data flow notation: This notation is denoted using arrows where the entire flow of data is represented and the direction in which it is flowing and going next in the system.
Benefits of data flow diagrams
The simplicity and ease of use of data flow diagrams are broadly effective in various industries and usage in different fields. They are:
- It is used in a software development tool that mainly focusses on the technical part and helps in researching elements by using pseudocodes.
- This is used by various business analysts all over the world to analyze and detect inefficient systems and help in the overall approach by uncovering the flaws or defects in the program.
- It helps small and mid-level organizations to lower the overhead costs, improve customer maintenance service, and provide better quality to users.
- It happens to be one of the powerful components for effective communication and rapid growth.
- It also helps the process or system to be analyzed to a deeper level of understanding and solving it to provide detailing.
Data flow diagrams prove to be one of the simple yet most powerful development tool inflowing of information at different fields, industries required for business purpose and the simplicity of diagrams makes it easy for us to comprehend.
This is a guide to Data Flow Diagrams. Here we discuss an introduction to Data Flow Diagrams, why we need it, how does it work, and benefits. You can also go through our other related articles to learn more –
- Cohesion in Software Engineering
- Software Configuration Management
- Software Quality Assurance
- Software Design Principles