Counting minimum cardinality patterns:\n“For every relationship, there are six possible sets of minimum cardinalities.”\nJudge the correctness of this statement for binary relationships.

Introduction / Context:
Minimum cardinality describes whether participation in a relationship is optional (0) or mandatory (1) for each entity. For binary relationships (involving exactly two entities), the number of possible minimum-cardinality combinations is finite and small. This question checks whether “six” is the correct count.

Given Data / Assumptions:

• We are discussing binary relationships only (two entities).
• Each side can be optional (0) or mandatory (1) independently.
• Notation (Crow’s Foot, IE, UML) may differ visually but expresses the same options.

Concept / Approach:
For a binary relationship, there are two independent yes/no choices: Is participation mandatory on the left side? Is it mandatory on the right side? Each choice has two possibilities (0 or 1). Therefore, the total number of minimum-cardinality patterns is 2 * 2 = 4: (0,0), (0,1), (1,0), and (1,1). The number “six” might arise from confusing minimum cardinality with total “cardinality classes” (1:1, 1:N, N:1, M:N) or by mixing minimum and maximum cardinality concepts. But strictly for minimum participation across two entities, there are four combinations.

Step-by-Step Solution:

Verification / Alternative check:
Consult any ER/EER methodology: Crow’s Foot and IE notations encode only these four minimum-participation states for binary relationships; “six” does not appear as a standard count.

Why Other Options Are Wrong:

• “Correct” contradicts the combinatorics.
• “Ternary relationships” involve three entities and have more combinations, but the question is framed for general relationships and commonly taught binary cases.
• Composite keys and notation do not alter the count of minimum participation states.

Common Pitfalls:
Confusing minimum with maximum cardinality; conflating relationship type (1:1, 1:N, M:N) with participation (optional vs mandatory).

Final Answer:
Incorrect