* Question

A simple DFD graphic description consists of the following four basic components, what are they?

* Answer

A simple Data Flow Diagram (DFD) consists of the following four basic components, which are essential to represent how information flows within a system:

1. Processes (Circles or Rounded Rectangles)

Description:

A process transforms incoming data flows into outgoing data flows. It represents an action or function performed on the data.

Example:

“Validate Order”

“Calculate Total”

Symbol:

Usually drawn as a circle, oval, or rounded rectangle, labeled with a verb-noun phrase (e.g., “Process Payment”).

2. Data Flows (Arrows)

Description:

A data flow shows the movement of data between processes, data stores, and external entities. It represents what data is being passed and in which direction.

Example:

“Customer Info”

“Order Details”

Symbol:

Drawn as a straight arrow, labeled with the name of the data (e.g., “Invoice Data”).

3. Data Stores (Open-Ended Rectangles)

Description:

A data store holds information for later use. It represents files, databases, or any repository from which a process can read or write data.

Example:

“Customer Database”

“Inventory File”

Symbol:

Drawn as an open-ended rectangle or two parallel lines.

4. External Entities (Squares or Rectangles)

Description:

Also known as terminators, these represent external sources or destinations of data that interact with the system, such as users, organizations, or external systems.

Example:

“Customer”

“Bank System”

Symbol:

Drawn as a rectangle or square, placed at the edge of the diagram.

Summary Table

These four components work together to provide a clear, structured view of system functionality and data movement, especially useful during system analysis and design phases.