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A Data Flow Diagram Dfd Information Technology Essay

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After solving the set of equations for all blocks of the DFG, the input and output are used to obtain information about the program such as its ‘basic blocks’ properties; for example, when does one block start and finish.

A data-flow diagram DFD is a graphical representation of the flow of data through an information system. DFDs can also be used for the visualization of data processing structured design.

On a DFD, data items flow from an external data source or an internal data store to an internal data store or an external data sink, via an internal process.

A DFD provides no information about the timing or ordering of processes, or about whether processes will operate in sequence or in parallel.

It is therefore quite different from a flowchart, which shows the flow of control through an algorithm, allowing a reader to determine what operations will be performed, in what order, and under what circumstances, but not what kinds of data will be input to and output from the system, nor where the data will come from and go to, nor where the data will be stored all of which are shown on a DFD.
A DFD is different from a flowchart, as a flowchart illustrates how an algorithm (that is part of a program) operates in terms of what order the algorithm will take place and the various conditions that may be associated with it, if any. A DFD on the other hand concentrates on how the data is affected by the algorithms. How and from where is the data inputted and outputted and how and where it will be stored.

When it comes to conveying how information data flows through systems and how that data is transformed in the process, data flow diagrams DFDs are the method of choice over technical descriptions for three principal reasons.

(Data Flow Diagram definition, blog source)

Requirements specifications is one of the most major thing for both developer and customer because they needed to fulfill what they wanted for the future specification and how its one layout look like are fairly important to them to meet their requirements they have needed to do it more in a formally requirements specification instead of just do it without procedure each and every steps are cautions they might be one mistake and the entire layouts might be lost just because of the simple mistake so this is why requirements specification are important

Definition question 1

DFD is a flow that is more specifically to stated how the flows and the process has been running through the entire process as it is one of the shortest way to understand how it is being processed by the DFD diagram

Answer for Question 1

Level-0 (Context Level)

DFD of a University Course Registration System

University Administration

University Course Registration System


Results Student details

Student Details

Course Details Course Details

Acceptance/ Denial







Inputted Details

Results Student Details Stu&

Student Course Cou

Details Details

Course Details

Denial Note

Check the information is all trueLevel-2 (Invalid Inputted Details)

Check the student is eligible for the course Student Student Student Details

Details Details

Course Details

Denial Note

Course details

Denial Note ( Not eligible) Result

Check that the results are true

And not tempered


Denial Note ( Invalid Result)

Level 2- Process Application

Issue Acceptance and inform faculty office

Store in Student Database Student Details Student Details

Student DB

Student Details

Store in Courses Database Course DB

Course Details

Course Details

Student Details Course Details

Acceptance Note

Data Flow

A data flow is either an input or an output of a process. The input data flow can be in various form such as a document, a record, a control signal transmitted by a transducer, a series of numbers keyed by a human operator and much more.

A data flow diagram does not take into account a series of spin-off scenarios; rather primarily follows a single path of information. However, this facility is applicable in case of flowchart diagrams. Scenario is a mandatory determinant in data flow diagrams assignments.

A Process or Data Transform

Data transform receives data as input and transforms it to produce output data.

Data Store

A data store represents as storage of data that is for used as input to one or more processes. Data store normally are computer database or manually operated files.

Our data flow diagram assignment experts point out that dataflow diagrams are not intended to answer procedural questions that are usually covered by flowcharts. For instance, a data flow diagram is eligible to represent an order delivery; however, it does not consider whether the order is taken virtually or in person, whether the data flow is taking place automatically or manually.

(Mohapatra, 2010)

External Entity

External entity represents the source or destination of data. Normally, an external entity may be both an originator and a receiver of data. Examples of external entity are a person, organization, hardware and so one.

Data flow diagrams (DFD) are a graphical representation of data flowing through an information system. A DFD represents a visual graphics of ‘data flow’ from the source, data processing and storage of data to sinks. In addition, DFD is specially designed for the analysis and modeling of the data processing system. However, data flow diagrams are primarily accompanied by ER models (Entity-Relationship) and data dictionary. We cater online data flow diagram assignment help taking into consideration the key components summarized below.

(Scott W Ambler, 2009)

DFD can be expressed as a series of levels. The outermost level, level 0 (exploded diagram of context diagram) shows how the system interacts. It is important to first draw context-level data flow diagram first before the level 0 to show all basic operations in the system.

In using the data flow approach of the system analysis and design, the system engineer first draws a context-level data flow diagram (level 0 DFD). This diagram shows the interaction between the system and external environment which acts as a data source and a data sink. In this level, the interactions between the system and the outside world are illustrated only as data flows that cross the border between them. The context diagrams show the entire system as a single process, and give no hint or idea about its internal organization. This level shows the overall context of the system and its operating environment and shows the whole system as just one process (represented by a black box). It does not usually show internal details of the design such as data stores.

(Kevin Bowman, 2004)

Data Dictionary

Data dictionary (DD) stores details and data about various components of a data flow diagram. It documents the details about the every system components such as data flows, data stores and processes.

Take swift data flow diagrams assignments help on these above topics from our professionals.

Because sometime certain phrases in the diagram may not understand by audience, data dictionary will be plays an important role to show common meaning to each system components.

(Mohapatra, 2010)

The following shows the data dictionary of Pizza World system.

Entity name: Student

Description: Person who are inquire to study in the university

Alternate name: Student

Output data flow: Result, Student Details, Course Details, Acceptance/Denial

Process name : University Course Registration System

Description : A system to designed for registration for any courses in the university

Alternate name : University Course Registration System

Output Name : Student details, Course details

Entity Name : Student

Description : Inputting all their data's in level 1

Alternate name : Student

Output Name : Result, Student, Details, Course Details

Input Name : Denial Note

Process Name : Inputted details

Description : Input a student details

Output : Student details, Course details

Process Name : Process Application

Description : To process a student details in a formal form

Output Student details, Course Details

Process Name : Check the information is all true

Description : Is to check whether the information that collects is true and no false statement

Input : Student details

Output : Denial note, Student details

Process Name : Check the students is eligible for the course

Description : It is to check whether a student is qualify to entrance our university

Output : Course Details, Student Details, Denial not eligible

Process Name : Check that the result are true and not tempered

Description : Check the student results

Input : Result

Output : Denial note invalid result

Process Name : Store in database

Description : To store student's information into database management system

Input : Student Details

Output : Student details

Process Name : Store in Database

Description :To store all the course's information

Input : Course Details

Output : Course Details

Process Name : Issue Acceptance and Inform Faculty Office

Description : To issue statement note that the student has acceptance in our university

Output : Acceptance Note, Student Details , Course Details

Define Question 2

A requirements specification is a comprehensive description of the intended purpose and environment for software under development.

The requirements specification fully describes what the software will do and how it will be expected to perform.
Data Flow Diagrams (DFDs) are directed graphs. There are two elements in the DFDs: arcs and nodes. Data is represented using arcs and circles are used to represent processes, which manipulate this data. Processes can be large and complicated but DFDs have the ability to repeatedly break processes down into small parts in order to show the sub-processes and their data flow. In addition to this, these sub-processes can be broken down further using DFDs in order to fully understand how they work and how the information flows between them. In essence, DFDs illustrate the structure of a system as an arrangement of linked processes that serve specific functions.

Answer for Question 2

Requirements specification is to describe how the system will do and not how it will be needed to be understandable by both developer and customer where they can run this system without any problem.

We should have enough information to develop a set of requirements for the system.

Requirements specification keeps project stakeholders and developers focused on the goals of the design.
A requirement specification is the customer's assurance that the development organization understands the problem and issue to be solved and the software behavior necessary to locate those problems. Therefore, it should be written in standard language, in an explicit manner that may also include charts, data flow diagrams, table, decision tables, and so on.

These requirements should also be used during quality assurance testing, to ensure that system features and functionality have been designed to support users, based on their needs and preferences.

There are several types of requirements for a website, including:

Data Requirements

Environmental Requirements

Functional Requirements

Usability Requirements

User Requirements

User Experience Requirements

Data Requirements

Data Requirements help developers understand how data will be gathered and used, so that they can plan and build a database with functionality that supports the information flow. When collecting information from a user on a website, it is important to understand how to store and format the information so that it may be used efficiently and in multiple ways.

Data Flow Diagrams (DFDs) are categorized as either logical or physical. A logical DFD focuses on the business and how the business operates. It describes the business events that take place and the data required and produced by each event. On the other hand, a physical DFD shows how the system will be implemented.

For example, if a website form requests a user's name, it is usually best to separate the name into First Name and Last Name fields, as another area of the web site may require users to alphabetize a list of users by their last name.
Show controls for validating input data, for obtaining a record, for ensuring successful completion of a process and for system security.

Another example is that many web sites personalize a user's experience by displaying "Welcome", followed by the user's first or last name only.

Environmental Requirements

The environment plays a powerful role in determining how to best communicate with users via your interface design. There may be cases where the users themselves have no visual, auditory or tactile deficits however, the environment in which they use the interface limits their normal perceptual abilities.

The system design phase is the development stage where the overall architecture and structure of the proposed system is decided. The system is divided into a set of sub-systems interacting with each other. Then, the specifications of each sub-system are defined by the system analyst as well as the requirements of the new system by the end user.

For example, in a hospital setting there may be 2 or more beeping machines around a patient during surgery, each with its own set of sounds. If you are designing a device that also includes sounds for alerts and alarms, you should learn about the sounds that the other machines make, so users can accurately distinguish the sounds coming from your device; otherwise, your sounds may not be useful to the user.
Any collection of attributes can be said to be either unnormalised or in a particular normal form depending on its compliance with the rules given below. Many normal forms have been defined. Codd originally defined first, second and third normal forms. There are some cases, particularly where keys are complex and contain many attributes, where further normalization may be required. For such cases, Boyce- Codd normal form, fourth normal form and fifth normal form also exist. In this book, normalization will only be covered up to the third normal form, since this is sufficient for most practical purposes. For further information about the other normal forms the reader is referred to Data (2000).

Another example of emerging technology on a large scale are touch screen devices, which are now in the hands of several million cell phone users with the advent of the iPhone and similar products. Touch screens may impose environmental constraints on a user due to clothing wearing gloves in cold weather, and they may be challenging to use while moving, such as when riding on a subway or in a car on a bumpy road.
In order to install the system, we first need to install the hardware first. Then we need to do the data entry for the items. We also need to install the software required to run the system.

Thus, Environmental Requirements are fundamentally important to an interface's design.

Functional Requirements

Once you have a list of features, you should describe how they should function in order to support users workflow the steps that users take to complete a task. It is also good to determine how one feature will interact with other features.

Are you in search for a reliable data flow diagram assignment help services? We have come up with baggage full of solutions to your homework help request. Drawing Data Flow Diagrams can be a stressful job if you are not well-versed with the crafting technique. The list of coursework help services we render is presented in details below.

Sometimes the interaction of two or more features can create new design problems related to functionality. The resulting list becomes your Functional Requirements.

Respondents are often eager to provide a wish list of desired features for an interface design.

Some of these may be fundamental features, some may add value competitively perhaps by enhancing the user experience, and still others may have been suggested to solve a usability issue inherent in the current design.
Efforts have been expanded to formulate guidelines for application of analysis and design principles based on data flow based methods. Analysis and design principles based on data flow-based methods are powerful means to support the requirements analysis process. They bridge the gap between requirements analysis and the computational aspects of data flow oriented models; and provide a systematic approach for effective structuring and managing complexity in the system under consideration.

Evidence of the latter group of features is often found in the workarounds that users create to bridge the gap between an existing interface design and a user's needs. For example, if a user must remember a 14-digit number in order to track a package being shipped, he may jot the number down on a sheet of paper to relieve his mind from the burden of memorizing it. This workaround suggests that users need an easier way to enter or remember this number, and designing the interface to accommodate the user would be ideal.
In the above equation, functioni is the function of the block i. It works on the input inputi, yielding the output Outputi. Figure 3 shows the graphical representation of block i.

An additional Functional Requirement could be to provide a way to recover or reset a lost password. It is important that Functional Requirements support user tasks the way that users actually perform or desire to perform them, and not how a web developer or researcher believes they should.
DFD is a system modeling tool, the most popular and important representations in data flow modeling. DFD allows us to picture a system as a network of functional processes, connected to one another by "pipelines" and "holding tanks" of data. It is a structured, diagrammatic technique representing external entities, logical storage, data sinks and data flows in the system. You can also call DFD as: bubble chart, bubble diagram, process model, and work flow diagram.

It is also important to exclude features that provide no real benefit or value to the user experience. For example, if someone on the project development team comes up with a feature idea, it should be tested with users before it is implemented.
Users as well as designers will be able to picture how the system will work, what will it achieve, and how it will be put together to achieve its objectives. The system developers may draw new versions of the system using new data flow diagrams and then compare these new DFGs with old system's dataflow diagrams and use these comparisons to implement a more efficient system.

You may discover that users perceive the feature as unnecessary, or worse, an obstacle on the path to achieving their goals.

Usability Requirements

An interface should be easy to learn how to use and easy to remember how to use. The latter pertains especially to devices that require infrequent use.

Other than data flow, system requirement specification also need to be focuses. A requirements specification is a document which is used as a communication medium between the customers and the supplier. When the software requirement specification is completed and is accepted by all parties, the end of the requirements engineering phase has been reached.

Users should not be required to consult a manual each time they need to use a kitchen blender for instance. Bank ATMs and web-based forms, which may be used by anyone, should be simple to use the first time around without instructions.
A data store represents the storage of data required and which it produced by the process. Examples of data stores: database, membership forms, and more.

Usability Requirements for an interface design should support the following from the perspective of its primary users:

Efficiency of use: goals are easy to accomplish quickly and with few or no user errors

Intuitiveness: the interface is easy to learn and navigate; buttons, headings, and help/error messages are simple to understand

Low perceived workload: the interface appears easy to use, rather than intimidating, demanding and frustrating

User Requirements

User Requirements define how to meet the physical and cognitive needs of the intended users of your website or application. Users should be able to comfortably and effectively use an interface to accomplish the goals that it has been designed to support.

DFDs play a major role in the design process as they allow users, as well as designers to picture how the system will work, what will it achieve, and how it will be put together to achieve its objectives. As well as this, DFDs provide users with the opportunity to see how their input affects the system as whole as well as adjacent parts of the system.

When you can clearly define who will be using your interface, and the environment in which it will be used, you can specify User Requirements. A Contextual Task Analysis is one method you can use to gain insights about how and where your users expect to use your interface, by observing how they currently perform a task that your interface will, or already does, support.
All the tasks shown above demonstrate an understanding of the modeling and installation of the data driven system. They demonstrate the analysis and design of a system including the prototype use interface, training plans for the users.

If you learn that a majority of your intended users have impaired vision, hearing, or motor skills, you may need to design your interface to support accessibility. For example, website form fields and error messages should support assistive devices such as text-to-speech readers.
A DFD aid the designers/end users to visualize how the information being inputted travels through the system. The main difference between the system flowchart and the DFD is that a DFD shows the flow of data through the software instead of hardware.

Another example is providing the ability to adjust font size small, medium, large to help users with impaired vision, which may include someone who does not always wear his or her glasses.

User Experience Requirements

User Experience Requirements have an impact on all other requirements. This is because in a User-Centered Design process, users come first.

To have a successful system design for the National Hostelling Association, I have to study the manual system first. Then I draw the context diagram. The context diagram shows the entire system as a single process surrounded by the external entities. The National Hostelling Association, Context diagram represents data input and output flows. This make to concentrate or focus on the boundary to be investigated. This can give great help in discussing with the user on the scope of the system.

Specifically, user needs and preferences for an interface design should be supported to the extent that they provide users an enjoyable experience and the means to complete their task goals with ease. A user's experience can be enhanced by adding elements of delight to user interactions.
The requirements specification is in result of a contract between the end user and the people that responsible for delivering the project.

Delight may manifest as unexpected by users shortcuts that allow a user to complete a common task more efficiently, or through the language used on a website when you speak the users language, you gain user trust.
The display area of the store is not very large. It will only display a small section of the Room & Other Sale Item that the Check in the Hostel room. My system will allow customers to choice rooms . This will allow customers to request room and service that are not on display. The customer can search the room by keyword or by category such as room,Booking No, CheckIn/Out etc or by charges. The charges will take the discount value for each invoice ie, the For manager, he will help with this activities during busy periods and will be responsible for the general management duties such as accounting, correspondence, staffing etc. The manager will also Booking and necessary from a number of customers and he will also decide which of the services will be discount prices to the customer. In order to do this, he will need the information from the system. The system also produce the monthly report in order to estimate the rooms status and the customer like and dislike of the services ie the customer trend according to the season.

To thoroughly understand user needs and preferences, conduct user research, such as one-on-one structured interviews, focus groups, and ethnographic observations.

(Project Management methodology, 2005)


DFD is definitely bringing much fastest way to understand such a complicated system and it compressed it into a very simplest way to the user or programmer to understand it. In this assignment, from what my illustration of DFD it is one of the simplest way me to compressed everything from a big stack of documentation which is complex and not easy to understand into simplest way in just a few levels of the flows and how it works between stages of levels from what their changes.

A data flow diagram should not include dozens of entities, attributes, flows and stores. Each DFD figure considers utmost six bubbles and other related stores. However, if a particular DFD seems complex, it must be simplified by breaking it into significant levels in your data flow diagrams assignments.

Requirement specification is one of the way to ensure the quality of assurance testing, in order to ensure the system features and functionality these has been designed for the support users based on the customer and developer needs.

Also formal languages are also very important for the developer and customer if one uses informal languages it may occurs and confuse by both developer and customer.
When developing a project, an agreement between the client and project team are formed. Document of requirement specification gave the information to client or customer regarding the project.


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