ER-Diagram is a pictorial representation of data which describes how the data is communicated and related to one another. Any object, like entities, attributes of an entity, sets of relationship and other attributes of relationship are characterized with the help of the ER diagram.
The Entity Relationship (ER) diagram components are as follows −
The use of an attribute or entity set generally represents an object. To check a real-world concept it is best expressed by an entity set or a relationship set. The use of any ternary relationship versus a pair of binary relationships occurs in the ER design decisions.
When we focus on the use of a strong or weak entity set, the following can occur −
The use of specialization/generalization − Contributes to modularity in the design.
The use of aggregation − It treats the aggregate entity set as a single unit without concern for details of its internal structure.