A unary relationship:

Question

BlackTom AI · Accepted Answer

A unary relationship is a type of relationship where an entity participates in the relationship with itself, which is commonly called a recursive relationship.
Option 1: 'must have the same cardinality at each end of the connecting line.' In unary relationships, the two ends may have different cardinalities depending on the scenario (e.g., an employee manages 0 or more employees, potentially with differing constraints), so this statement is not universally true.
Option 2: 'Has maximum and minimum cardinality of one.' This would describe a binary or restricted one-to-one scenario, but unary relationships can have varying cardinalities (one-to-many, many-to-many, etc.) depending on the model, so this is too restrictive.
Option 3: 'does not require any indication of cardinality.' In data modeling, cardinality is a key aspect of a relationship, and unary relationships typically specify cardinality to convey the allowed number of participations, making this statement inaccurate.
Option 4: 'is also known as a recursive relationship.' This accurately describes a unary relationship, where the relationship is with the same entity type and is conceptually recursive.

BUSI_V 335 101 102 2025W1 Module 10 Quiz - Design Notation and Software

A unary relationship:

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