How many entity-set roles participate in a quaternary relationship in E–R…
2021
How many entity-set roles participate in a quaternary relationship in E–R modelling?
Answer: C. 4 — ConceptThe degree of a relationship in an E–R model is the number of participating entity-set roles in the relationship set. A relationship instance links…
- A.
2
- B.
3
- C.
4
- D.
5
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Show answer & explanation
Correct answer: C
Concept
The degree of a relationship in an E–R model is the number of participating entity-set roles in the relationship set.
A relationship instance links entity instances, while the schema-level degree counts the roles through which entity sets participate; one entity set may occupy more than one role in a recursive relationship.
Application
The prefix quaternary denotes degree 4. Therefore, a quaternary relationship has four participating entity-set roles.
Contrast
A degree of 2 is binary.
A degree of 3 is ternary.
A degree of 5 is quinary, so it is beyond the quaternary case.
Cross-check
Counting the participating entity-set roles gives 4, which agrees with the prefix quaternary. The result is 4.