What is Data Flow Diagram? What does it mean?

Data Flow Diagram what? If you are not familiar with this type of diagram, you will feel confused about the meaning and how to build a complete diagram. This tool can be difficult to access for people who are not too tech-savvy because it includes many levels, symbols with different meanings.

Hope through this post lamchutaichinh.vn can answer your questions, introduce you to the indispensable benefits of Data Flow Diagram for the management system at the enterprise.

What is a Data Flow Diagram (DFD)?

A Data Flow Diagram (DFD) is a traditional way of simulating a system's data flows in a neat and clear way in the form of diagrams.

Here, data changes, data storage, data input and output are described rigorously, so that you can visualize the scope and boundaries of the system easily. and most accurate.

The Data Flow Diagram was widely used in the 1970s in the field of software development. Larry Constantine and Ed Yourdon first described data flow diagrams in an ancient text.

Since then, data flow diagrams are applied and increasingly improved to meet more complex systems and bring higher efficiency to users.

The Data Flow Diagram uses symbols with distinct display meanings such as: rectangles, circles, ovals, arrows and short text labels.. to represent the flow of flow from a process or function. function to another process and function.

Thanks to DFD, you can visualize in detail the operation of any complex system with many different information components and processes, thereby identifying the stages of inefficiency and improve as quickly as possible.

Depending on the level of the Data Flow Diagram, the data flow can describe you from an overview of the system being operated, to an in-depth diagram that describes the data and its interactions. relation between them. Therefore, data flow diagrams can be applied in many fields such as information technology, business..and always bring efficiency.

So what are the components in the Data Flow Diagram? Let's find out with lamchutaichinh.vn right here.

Components in the Data Flow Diagram

A Data Flow Diagram (DFD) will have 4 components as follows:

Process (Process): a process that alters input data to produce output data. Processes have different levels and functions. By dividing large processes into smaller ones, the level of detail in the process is reflected in how data is processed and transformed after each process.
External Entity: this can be a customer, an affiliated business or a subsidiary, a bank... these external units play the role of exchanging information with the main system.
Data store: is where the necessary data is stored and the data is generated throughout the process. Specifically, they can be mentioned as tables, employee forms, goods statistics, warehouse papers, invoices..
Data Flow: the route back and forth between data and process, external unit and data warehouse will be shown by arrows.

Analyze the data flow of the system

Before proceeding to create a data flow diagram, you must analyze the data flow of the operating system fully and logically.

Business Function Diagrams (BFDs) are used to perform analysis and break down a system into processes with smaller functions, we will have a rough diagram where specific locations can be found. of each process in the system and avoid redundancy or duplication in research and system administration. The output of the BFD diagram is the premise for the data flow diagram.

Meaning of Data Flow Diagram (DFD)

Data Flow Diagram is an effective support tool that system analysts, data analysts, business development teams, product development teams .., can apply to bring the following benefits. a simple and fast way:

Analysis: DFD allows business development or product research teams to track data related to customer-product interactions, product flow from input to output, and product sales performance. as well as customer acceptance. Tracking the flow of this data will help professionals to target improvement or adjust the plan to suit the actual situation.
Expressions: this is a relatively simple method of communication between the system data analyst and any individual who has a role in the system. Information flow diagrams shorten data flow visualization time significantly.
System design: data flow diagram will help data analyst easily map out all the information related to the system so that data can be connected together visually. This will be the premise for setting up a plan or a whole new system.
Where to store data and monitor data flow: this is the place to store all data related to the system from the data needed for each process to the data that has changed according to the flow of the process. The Data Flow Diagram will show what happens to a data source, when it was created, where it went, ended or stored. From there, when there is a need to retrieve data, it will also be easier and faster.

Hierarchies in data flow diagrams (DFDs)

Here are the different levels of DFD:

DFD level 0

Level 0 data flow diagrams are also known as context diagrams. It is designed in a simple way to show an overview of an entire system or process.

At this level the viewer can quickly grasp where input data passes through the main process then transforms into output data, indicated by incoming and outgoing arrows.

DFD level 1

The level one diagram will be described more specifically than level 0 by dividing the main process into smaller processes and adding relevant data.

It provides a more detailed view from the context diagram, where the main process is shown in relation to the smaller processes by arrows.

DFD level 2

This is a more granular level, where the diagram further breaks down the level 1 processes into smaller processes and comes with more detailed data. The data is linked to external entities and additional databases.

Here detailed data and links with external entities will be added to build a data flow diagram that describes the current system in the most detail.

Data Flow Diagram (DFD) building process

To build a complete and logical data flow diagram, the simplest way is to rely on the BFD diagram. As mentioned above, the business function diagram will divide the system into functional parts from large to small, based on this diagram depending on the large and small scale and the purpose of making the diagram, choose a DFD with a low level. suitable.

Basically, the process of building a Data Flow Diagram has 5 steps as follows:

Step 1: Build a complete BFD diagram

This will be the premise for us to know where each specific large and small process is in and the relationship between them in the system. Once you have an overview of the system, the DFD will be built in a complete and logical manner, avoiding data redundancy or duplication.

Step 2: Build DFD level 0

This is the time to show an overview of the main process's connection to data as well as external factors.

Here you will have to present what is the input, after going through the main process of the system you will get what is the output. This is the simplest step but serves as the backbone for the development of DFDs to the next level.

Step 3: Expand the diagram to level 1

From the context diagram, on the basis of breaking down the main process into smaller processes, there will be data flows, external factors and general data warehouses corresponding to those processes.

Subdividing as well as adding related data will make the diagram more detailed and complete.

Step 4: Upgrade to level 2

Similar to the above, you continue to break down the process from level 1 and then add the necessary components and data to your diagram.

If you want a DFD with more detail you can continue to upgrade to level 3 or more, but usually level 2 you already have a detailed enough datamap.

Step 5: Check DFD . Accuracy

After you have completed the data flow diagram, you need to check the entire diagram to make sure you have not missed any processes or data. Testing should be done by many people with different ranks to get the most detailed view of the diagram.

Also, check that the diagram is really enough for partners or other stakeholders to understand your system when viewing. From there, it is possible to verify the effectiveness of the Data Flow Diagram or detect errors and promptly correct them.

Conclude

Hopefully lamchutaichinh.vn has answered your questions about what is Data Flow Diagram, the meaning and effectiveness that this diagram can bring to your business through this article.

This will be an extremely useful support tool for you to set up and improve your system. Good luck building a data flow diagram.

Information edited by Lamchutaichinh.vn