If two attributes, P and Q, satisfy the functional dependencies P→Q and Q→P, then the relationship between P and Q is:

Correct option is E

When both P→Q and Q→P hold true, it establishes a bidirectional dependency between P and Q. This implies that the values of P uniquely determine the values of Q and vice versa. Such a relationship signifies that the two attributes are interchangeable for determining each other in the given context.
Important Key Points:
1. Bidirectional Dependency: This occurs when two attributes mutually determine each other (P→Q and Q→P).
2. Mutual Dependence: This relationship is symmetric, meaning either attribute can act as the determinant of the other.
3. Unique Determination: Both P and Q are necessary to preserve the integrity of the relationship as they rely on each other.
Knowledge Booster:
· Partial Dependency: Happens when a non-prime attribute is dependent on a part of a candidate key, not applicable here as both attributes are fully dependent on each other.
· Full Functional Dependency: Occurs when a non-prime attribute is fully dependent on the entire candidate key, which is different from bidirectional dependency.
· Transitive Dependency: Exists when an attribute depends on another attribute indirectly through a third attribute. This is not the case here.
· Multivalued Dependency: Refers to scenarios where one attribute determines multiple values of another attribute, which is unrelated to the given functional dependencies.