Question

Which one of the following is about a specific attribute that is guaranteed to take a unique value?

• A. Inverses
• B. Existence in an is-a hierarchy
• C. Techniques for reasoning about values
• D. Single valued attributes

Hint:

A single-valued attribute ensures that each entity holds only one value for that specific property, unlike multi-valued attributes where multiple values can exist.

Answer 1

The Correct Option is D

Step 1: Understanding Attributes in Data Systems Attributes describe properties of an entity in a database or knowledge system.
Step 2: Analyzing the Concept of Single-Valued Attributes
- A single-valued attribute is one that can only have one distinct value for a given entity.
- Example: A person's date of birth is a single-valued attribute since an individual can have only one date of birth.
Step 3: Explanation of Options
- Option (A) Inverses: Incorrect, as inverse attributes represent relationships between entities.
- Option (B) Existence in an is-a hierarchy: Incorrect, as it refers to classification structures in hierarchical data.
- Option (C) Techniques for reasoning about values: Incorrect, as it focuses on inference and reasoning rather than uniqueness.
- Option (D) Single-valued attributes (Correct): This refers to attributes that are guaranteed to take a unique value.