Data Flow Diagram Homework Help


Data Flow Diagram

Data Flow Diagram

A Diagram in a Computer Science is representing a process of any software system. A Data Flow Diagram represents the data flow in the form of statistical models representation of a system.

Mostly Data Flow Diagram transfers the system data as an input to file storage and starts making. Data Flow Diagram is also known as DFD.

which implements functions manipulate them and represent them graphically also stored them into various parts of a system. Data Flow Diagram have types which is mentioned in the coming para.

Types of DFD:

Data Flow Diagram (DFD) has two types which are as following:

  • Logical or context data flow diagram.
  • Physical or levelling data flow diagram.

Logical Data Flow Diagram:

A type of DFD that is used to make the purpose of generating a profit easier and it only focus on the business models. The diagram explains completely of what is going on in the model. It does not take action about how the system is performing.

It helps the project managers to explain easily about the flow of business models.

Physical Data Flow Diagram:

A physical DFD works physically generates the working of a system.

It completely defines about the process of the system of how it works in the form of DFD. It includes the hardware of a computer as well as software of a computer. Also it keeps tracks of computer files and the user data of the system.

It also fulfilled the concept of automated and manual process and align them separately.

Data Flow:

Data Flow is the symbol of DFD that represents the flow of data and traverse them to one another. A Data Flow cannot be null it contains at least one data in it it could be any type of data it could store as small data as one or large & complex data as many. The most common rule of Data Flow that it must end in one step that is processing. It implements the thumb rule so that data flows in one and straight Position in Data Flow.

Data Store:

A data store is a symbol of DFD that stores data from any storable resource that is data base or a text file.


A process is a symbol of a DFD that inserts data as an input retrieve it and generates output. It can be easier as well as complex DFD’s of generation of data.


It is a rectangular surface that records process and collect data from data store and give the process ID to make traversing easier.

External Entity:

External Entity have the data source from that contains any type of data. It exports the data outside from the system.


In this Technique of DFD the leveling of data should expand in lower level DFD’s and expanding a lot until it is not reach its desired position. The lower level DFD’s expands iteratively one by one until all the functions were performed.

DFD Balancing:

It is compulsory in DFD that the lower nodes which expands with the Top down technique of DFD should be balanced in n and n+1 nodes.

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