Concept of system design tools

Concept design tools is a process for create new neat and clean plan of System development. We can create new system's process, using various Component.  

Data flow diagram (DFD)

  • A Data Flow Diagram (DFD) is a traditional visual representation of the information flows within a system. 

  • A neat and clear DFD can represent by a drawing,a good amount of the system requirements graphically.

  • It can be manual, automated, or a combination of both.

  • It diagrammatic representation of a process, system, sub-system etc.

Data flow diagram Components:

1. Process:

A process is a business activity or function where the manipulation and transformation of data takes place.

2. Data store:

Datastore is a central location of data. It holds the data that is retained in the system.

3. Data flows:

  • It is represented by the joining arrow. It connects... 
  • Between the process 
  • Form data store to process
  • Process to data store 
  • Source to process
  • Process to sink(higher to lower position) 

4. External entities: 

Entity Relationship Diagram (ERD)

  • An Entity Relationship (ER) Diagram is a type of flowchart that illustrates how “entities” such as people, objects or concepts relate to each other within a system.
  • It is a logical structure of a database that can be expressed graphically.
  • It is the process of database design and the simplicity and pictorial clarity of the database design technique.
  • ER diagrams use a defined set of symbols such as rectangles, diamonds, ovals and connecting lines to depict the interconnectedness of entities, relationships and their attributes. 


A definite thing—such as a person, object, concept or event—that can have data stored about it. Think of entities as nouns. Examples: a customer, student, car or product. Typically shown as a rectangle.


A property or characteristic of an entity. Often shown as an oval or circle.

For example: faculty _sub, depart_name, stu_num, Class_roll etc.


How entities act upon each other or are associated with each other. Think of relationships as verbs. For example, the named student might register for a course.

It represented by diamond 


The flow of information is indicated by the lines in RE Diagram. 

It is represented by a line.

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