Data Flow Diagram | Business Assignment

Added on - 01 Oct 2019

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2Blog WritingData Flow DiagramJuly 25th, 2019What is Data Flow Diagram?In a business information system, some of us have noticed a graphical representation of theentire flow of data taking place with the help of a diagram. This diagram is known as a dataflow diagram or DFD. A data flow diagram is a graphical representation of the flow of datataking place in a business information system. It provides ample information about customerdetails, account details, transaction history, deposit amount, withdrawn amount, updatedaccount balance, orders placed, details of the brokers, etc. The processes which are involvedin a business information system in transferring data are graphically represented with the helpof the data flow diagram. The data get transferred to the file manager from the inputs togenerate reports. We can find physical and logical data flow diagrams. The physical data flowdiagram mainly describes the physical implementation of data flow on the logical ground. Onthe other hand, the flow of data through a particular system in performing certain specifiedfunctionalities of business is described by the logical data flow diagram. It is important tounderstand why a business information system needs to represent the flow of data transferwith the help of either logical or physical data flow diagram. The graphical representationtaking place through DFD helps in representing the processes and the functions which arecapturing manipulating, storing, and distributing data between the environment of aninformation system and the entire information system and also between various systemcomponents. These elements get represented graphically with the help of the data flowdiagram.Data flow diagram helps in providing logical information and the flow of businessinformation system. It also helps in determining the requirements of physical systemconstruction. It enhances notation and simplicity and establishes automatic and manualsystem requirements. There are mainly four symbols of data flow diagram such as process,data store, external entity, and top-down decomposition technique. The process receives datainput and provides output with a different form or content. We can have a simple processwhere data are collected and saved in the database. On the other hand, we can also have acomplex process where a report is produced which contains details of monthly sales of anyretail stores. Every process gets assigned with a particular name which helps in identifying
3Blog Writingtheir functions or performance. Data flow indicates a path through which the data from oneend of the information system moves to the other end. It may represent an element of data.For example, customer id can be represented in a data flow. Datastore is the repository ofdata which is used in representing a situation in the data flow diagram. The situation which isrepresented by data stored indicates the retention of data in the system. It is very important inthe data flow diagram because single or multiple processes are needed in the usage and therecorded data in the data store are used for future references. Top-down decompositiontechnique is also known as leveling. It is a method which is used to portray detailedinformation of the lower-level data flow diagrams.Leveling is produced by the help of a series of diagrams having more detailed informationuntil the desired detailing gets achieved. An external entity is a department or a person or anoutside organization which provides information and data to the information system and alsoreceives output from the information system. External entities can also be defined as thecomponents found in the outer boundaries of a business information system. The externalentities help represent the interactions between the outside world and the information system.The external entity is represented by a rectangle in the data flow diagram. These externalentities either receive data or supply data but they do not process data. There is a differencebetween physical and logical data flow diagrams. The physical data flow diagram portraysthe ways the system would be implemented. On the other hand, logical data flow diagramportrays on the ways business gets operated and it mainly focuses on the core areas of thebusiness.Two types of Data Flow Diagram-Logical and Physical Data Flow DiagramLogical Data Flow DiagramThere are two types of data flow diagram logical and physical data flow diagram. Logicaldata flow diagram is that type of data flow diagram which mainly focuses on businessactivities and the business as a whole. It can be considered as the fundamental basis ofphysical data flow diagram because by modifying the logical data flow diagram, we can getthe physical data flow diagram. Logical data flow diagram explains data and business eventswhich are necessary to accomplish the business events. A physical data flow diagram can bedeveloped based on a logical data flow diagram. Physical data flow diagram depicts theworking of the data in the system with the support of paper files, Software, Hardware, and
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