Relational database theory: any table that meets the formal definition of a relation is, by definition, in First Normal Form (1NF). Is this statement accurate?
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ACorrect
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BIncorrect
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CApplies only to primary keys
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DDepends on referential integrity only
Answer
Correct Answer: Correct
Explanation
Introduction / Context:First Normal Form (1NF) is the foundational requirement in relational database design. The statement claims that if a table meets the formal definition of a relation, then it is already in 1NF. Understanding what a “relation” means in the relational model clarifies why this is considered correct in most database textbooks and industry practice.
Given Data / Assumptions:
- A “relation” refers to the formal construct of the relational model, not just any arbitrary spreadsheet-like table.
- Attributes (columns) are defined over domains of atomic (indivisible) values.
- There is no inherent ordering of rows (tuples) or columns (attributes), and there are no duplicate rows in a relation.
Concept / Approach:1NF requires that every attribute value is atomic (no repeating groups, no arrays in a single cell), and that the table behaves as a mathematical relation: unordered tuples, unordered attributes, and no duplicate tuples. The classical definition of a relation already encompasses atomic domains and these properties, so a structure that truly satisfies the definition of a relation is, by construction, in 1NF.
Step-by-Step Solution:
Identify the formal properties of a relation: no row order, no column order, no duplicate rows, and atomic values.Compare with 1NF requirements: atomic attribute values and tabular structure with one value per cell.Conclude that meeting the relation definition implies meeting 1NF constraints.Verification / Alternative check:Check any table: if a cell stores multiple values (e.g., comma-separated lists), it violates atomicity and thus fails to be a relation; therefore it also fails 1NF. Conversely, when all cells are single, indivisible values and other relation properties hold, it is considered 1NF.
Why Other Options Are Wrong:
- “Incorrect” contradicts standard theory equating relations with 1NF tables.
- “Applies only to primary keys” misunderstands that 1NF applies to all attributes, not only keys.
- “Depends on referential integrity only” confuses normalization with relationship constraints between tables.
Common Pitfalls:Confusing a spreadsheet or denormalized table (with lists in cells) for a relation. Also, thinking that 1NF concerns foreign keys; it does not—those are separate design concerns.
Final Answer:Correct