In a proper relation (relational model), does the physical or logical order of rows (tuples) matter for meaning or correctness?

Introduction / Context:
The relational model treats a relation as a set of tuples. Sets do not have ordering. This question probes whether row order is semantically meaningful in a relation and whether changing row order could alter the meaning of the data.

Given Data / Assumptions:

• A relation is a set (or multiset in implementations, but conceptually a set) of tuples.
• Set semantics imply no intrinsic ordering.
• Queries may apply ORDER BY to request a presentation order, but that is outside the relation’s definition.

Concept / Approach:
Because a relation is a set, any physical order on disk or logical order in memory is irrelevant to its meaning. SQL implementations often return rows in unspecified order unless ORDER BY is used. Therefore, the statement “the order of the rows matters” is false in the formal sense.

Step-by-Step Solution:

Verification / Alternative check:
Run the same SELECT multiple times without ORDER BY; the database may choose different access paths and return different row orders. The data content remains the same, confirming order irrelevance.

Why Other Options Are Wrong:

• “Correct” conflicts with the set-based definition.
• Mentions of indexes or exports are implementation details and do not make order semantically significant.

Common Pitfalls:
Assuming that because a clustered index stores rows in index key order, the relation “has” an order. That is storage, not logical meaning.

Final Answer:
Incorrect