Difference Between DFD And ERD

DFD (Data Flow Diagram) and ERD (Entity Relationship Diagram) models both show data presentations for identifying data flows. Organizations use such models to effectively communicate within different divisions.

Data means information, flow means to maneuver and diagram means a picture to represent something. So, Data Flow Diagram (DFD) is solely the graphical representation of the flow of information or information. It’s a framework or pattern of information systems. It includes data input, data output, storing data. DFD describes the method of taking the information as input, storing the info, giving the info as output. DGD describes the trail of knowledge that completes the method. There are mainly two varieties of DFD: Physical Data flow sheet, and Logical Data multidimensional language.

Entity means any object wont to store information and is distinguishable, relationship means connection, and diagram/model means a picture uses to represent something. So, Entity Relationship Diagram (ERD) is just the diagram or model that’s wont to represent or show the connection between the entities or data objects that are stored in a very database. the most components of the E-R model are an entity, attributes, and relationship. it’s really easy thanks to representing the database design.

The key difference between DFD and ERD –

  • DFD shows how data enter a system, is transformed in that system, and how it is stored in it.
  • ERD represents the entity model and will show what a system or a database will look like but not explain how to implement it.
  • DFD shows what “things” or procedures transform inputted data into some output, as well as WHERE data is stored.
  • ERDs model WHAT kind of data and what relationships do different pieces of data have with each other. It would define the structure of our database tables.
  • DFDs main objective is to represent the processes and data flow between them.
  • ERDs main objective is to represent the data object or entity and the relationship between them.
  • DFD explains the flow and process of data input, data output, and storing data.
  • ERD explains and represents the relationship between entities stored in a database.
  • DFD model is a multi-level representation that commences with abstract information and includes multiple decomposed levels.
  • ERD model represents the system data and includes an elaborate description of the relation between the data.
  • DFD is not enough to completely describe a system; it cannot also specify computations in a process.
  • ERD does not show the interaction between the model or data and how it changes in a system.
  • DFD is usually processed individually based on certain aspects, where each of them could be linked interactively.
  • ERD often represents a group of similar things; it shows how the data units are grouped into entities logically.
  • Symbols used in DFD are: rectangles (represent the data entity), circles (represent the process), arrows (represent the flow of data), ovals, or parallel lines (represent data storing).
  • Symbols used in ERD are: rectangles (represent the entity), diamond boxes (represent relationship), lines, and standard notations (represent cardinality).
  • The rule followed by DFD is that at least one data flow should be there entering into and leaving the process or store.
  • The rule followed by ERD is that all entities must represent the set of similar things.

DFDs and ERDs are should be created and maintained using business processes and data modeling tools, i.e. software that supports the methods of decomposition and outline further because of the method-related rules of consistency and integrity. High-quality modeling tools will foster the exchange of labor items between DFDs and ERDs, e.g. to enforce naming standards.


Information Sources:

  1. differencebetween.net
  2. edrawsoft.com
  3. geeksforgeeks.org