In entity–relationship (ER) modeling, the UML term “multiplicity” corresponds most closely to which ER concept?

Introduction / Context:
In Unified Modeling Language (UML) class diagrams, associations show how classes relate, and the numbers on each end of an association (for example, 0..1, 1, 1.., * ) are called multiplicities. In Entity–Relationship (ER) modeling, we express the same idea using cardinalities such as one-to-one, one-to-many, and many-to-many. This question tests your ability to map UML terminology to classic ER modeling terminology.

Given Data / Assumptions:

• We are comparing terms between UML (object-oriented analysis/design) and ER (data modeling).
• Multiplicity in UML conveys the allowed number of associated instances at each end of an association.
• ER models describe participation counts between entity types using cardinality.

Concept / Approach:
Interpret “multiplicity” (UML) as the constraint on how many instances of class A can be linked to an instance of class B and vice versa. In ER modeling, the directly corresponding concept is “cardinality,” which specifies minimum and maximum numbers of relationships (for example, one-to-many). Therefore, the correct cross-reference is multiplicity ↔ cardinality.

Step-by-Step Solution:

Verification / Alternative check:
Check a UML association labeled 1..* from Order to OrderLine. In ER, the same relationship is one Order to many OrderLines. The numerical constraint is the cardinality on the ER side, which mirrors multiplicity on the UML side.

Why Other Options Are Wrong:
Relationship: the link itself, not the count of instances.
Attribute: describes properties, not participation counts.
Entity: represents an object/class, again not the numeric constraint.

Common Pitfalls:
Confusing participation (minimums) with cardinality (maximums). In many texts, “multiplicity” summarizes both; in ER, minimum participation and cardinality are often described separately.

Final Answer:
Cardinality