A visual representation of entities and connections is known as an entity-relationship diagram (ERD). This style of graphic is frequently used in databases and information systems to represent semi-structured or unstructured data. ERD appears to be comparable to a flowchart at first look. ER diagrams are used to represent a framework system in a more comprehensive, easy and clear way. Rectangles, Ellipses, Diamonds, Lines, Primary keys are the main components of an ER diagram. Rectangles are used to depict the entity types and ellipses are used to depict attributes. Diamonds are used to represent relationships. Lines link attributes to entity types and entity types with other relationship types.
