An attribute set X is a Super Key of relation R if and only if:
An attribute set X is a super key if its attribute closure under F (X+) determines every attribute in relation schema R. In the revised options, none of (A), (B), or (C) states the required condition, so (E) is correct.
An attribute that is part of ANY candidate key of a relation schema is called a:
A prime (or key) attribute is any attribute that belongs to at least one candidate key of the relation. Non-prime attributes belong to no candidate key. Therefore, none of the first three statements is correct.
Given relation R(A, B, C) with F = {AB -> C, C -> A}. What are the candidate keys of R?
(AB)+ = {A, B, C}, so AB is a candidate key. Also (BC)+ = {B, C, A} since C -> A, so BC is also a minimal super key. Hence, candidate keys are AB and BC.
What is the primary objective of Database Normalization?
Normalization organizes relational tables to minimize data redundancy, avoid insertion, deletion, and update anomalies, and enforce data integrity. The revised options contain two correct statements, so (D) is the appropriate choice.
Which update anomaly occurs when deleting certain data unintentionally causes the loss of other unrelated, valuable data?
A deletion anomaly occurs when deleting one piece of data results in the unintentional loss of entirely separate information (e.g., deleting the last student enrolled in a course inadvertently deletes the course information).