Match the building blocks in Entity Relationship Diagram.
2021
Match the building blocks in Entity Relationship Diagram.
- A.
i-b, ii-c, iii-a, iv-d
- B.
i-b, ii-c, iii-d, iv-a
- C.
i-c, ii-b, iii-d, iv-a
- D.
i-b, ii-a, iii-d, iv-c
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Correct answer: B
Entity Relationship Diagram - It is a diagram that displays the relationship of entity sets stored in a database. In other words, ER diagrams help to explain the logical structure of databases. ER diagrams are created based on three basic concepts: entities, attributes and relationships.
Relationship - It is nothing but an association among two or more entities. Entities take part in relationships. We can often identify relationships with verbs or verb phrases. It is represented by a Diamond.
Attributes - It is a single-valued property of either an entity-type or a relationship-type. It is represented by an Oval.
Optional One - It represents a relationship between two entities that is NOT mandatory to exist. It is represented by a line intersected with a vertical line and an oval at one end.
Mandatory One - It represents a relationship between two entities that is mandatory to exist. It is represented by a line intersected by two small vertical lines at one end.