What does First Normal Form (1NF) require in a relational table?

• A. Atomic column values
• B. No repeating groups
• C. All attributes depend on the primary key
• D. Data stored in nested structures

Answer: (A)

1NF requires that each cell in a table holds a single, indivisible value. This atomicity means you can’t store lists, sets, or multiple values in one field. If a field could contain multiple values, the data isn’t in 1NF because the value isn’t atomic, which makes reliable querying and data integrity harder. While you’ll often hear that 1NF means no repeating groups, that describes the same idea in practical terms: removing multi-valued attributes so every cell contains only one value. The other statements point to later normalization concerns or structures that would violate 1NF, not the fundamental requirement. So the best answer is atomic column values.