Diagnostic Answers — DM5-013–024
DM5-013 — A
Why: cardinality expresses how many instances may/must participate, including optionality.
Distractors: B is attribute count; C is arity; D is unrelated.
Source: pp. 132–134. Confusion: cardinality vs arity.
DM5-014 — B
Why: arity counts participating entity types.
Distractors: A is cardinality/optionality; C is row volume; D is key construction.
Source: pp. 133–134. Confusion: arity vs cardinality.
DM5-015 — C
Why: Employee relating back to Employee is unary/recursive—one entity type.
Distractors: binary/ternary require 2/3 types; identifying status is a different relationship property.
Source: p. 134. Confusion: unary vs binary vs ternary.
DM5-016 — D
Why: Supplier + Product + Location simultaneously requires a ternary relationship.
Distractors: unary/recursive = one type; binary = two.
Source: p. 134. Confusion: binary vs ternary.
DM5-017 — A
Why: a foreign key is a migrated parent/related key used to represent the relationship relationally.
Distractors: encryption/text datatype/only-key claims are unrelated or false.
Source: current answer key pp. 134–138. Confusion: foreign key vs primary key.
DM5-018 — B
Why: identifying means the migrated parent PK participates in the child's PK.
Distractors: A describes non-identifying; C/D do not show identifying migration.
Source: current answer key pp. 137–138. Confusion: identifying vs non-identifying.
DM5-019 — C
Why: non-identifying retains the parent reference as a FK without making it part of the child PK.
Distractors: A is identifying; B is arity; D optionality alone does not determine identifying status.
Source: pp. 137–138. Confusion: identifying vs non-identifying.
DM5-020 — D
Why: a dependent entity's identifier relies on attribute(s) contributed from another entity.
Distractors: attribute count, any relationship, or surrogate use alone do not define dependence.
Source: pp. 137–138. Confusion: independent vs dependent entity.
DM5-021 — A
Why: simple = one attribute; composite = 2+.
Distractors: business meaning, surrogate status, and FK role are separate classification dimensions.
Source: pp. 135–137. Confusion: simple vs composite.
DM5-022 — B
Why: compound is the more specific composite form whose components are foreign keys.
Distractors: A is simple; C is surrogate behavior; D is not a source restriction.
Source: pp. 135–137. Confusion: composite vs compound.
DM5-023 — C
Why: surrogate = system-generated identifier with no business meaning/intelligence.
Distractors: A = business key; B = alternate key; D = compound construction.
Source: pp. 136–137. Confusion: surrogate vs business key.
DM5-024 — D
Why: super key = any unique set; candidate = minimal unique set with no unnecessary component.
Distractors: generated/business meaning is separate; primary is only one selected candidate; candidates must be unique.
Source: pp. 136–137. Confusion: super vs candidate key.