What is the difference between dfd and er diagram

The logical DFD illustrates the processes involved without going into detail about the physical implementation of activities. Note that the Context Diagram did NOT record the movement of merchandise, but rather the information flow surrounding the underlying business processes. Let's summarize their differences:. We use cookies to offer you a better experience. By visiting our website, you agree to the use of cookies as described in our Cookie Policy.

Logical vs Physical Data Flow Diagrams. Flow Chart : Flowchart is a diagrammatic representation of an algorithm. Sometimes programmers use it as a program planning tool to solve a problem. It makes use of symbols which are connected among them to indicate the flow of information and processing. It is a convenient technique to represent the flow of control in a program. Data Flow Diagram DFD : Data refers to information, flow refers to move, and diagram refers to a picture to represent something.

So, DFD is basically the graphical representation of the flow of data or information. It is a framework or pattern of the data systems.

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. The ERD model represents the system data and includes an elaborate description of the relation between the data.

DFD is represented by ovals, rectangles, or circles and is named with a single word. Arrows represent the flow, and ovals or parallel lines represent the storings. The ERD is represented by a rectangular box, and diamonds represent the relationship between the entities. Cardinality is represented by lines or standard notions. Both these data models also come with many different shortcomings. DFD is not enough to completely describe a system. Moreover, the use of different symbols can create confusion in the users.

The DFD cannot also specify computations in a process.