Do denormalized tables, by definition, satisfy Boyce–Codd Normal Form (BCNF)? Consider the typical practice of intentionally merging attributes to reduce joins.

Introduction / Context:
Denormalization is the deliberate introduction of redundancy to improve read performance or simplify queries. BCNF, in contrast, eliminates redundancy caused by certain functional dependencies. This question probes whether the act of denormalization is compatible with BCNF.

Given Data / Assumptions:

• Denormalization often combines tables or repeats derived attributes.
• BCNF requires every determinant to be a candidate key.
• Design goals may include minimizing joins for heavy reporting.

Concept / Approach:
When attributes that depend on a non-key determinant are merged into one table, new dependencies are introduced where determinants are not keys. That contradicts BCNF. Therefore, denormalized tables generally do not meet BCNF, although they may still be correct and useful with proper controls (constraints, ETL, audits).

Step-by-Step Solution:
List functional dependencies for the table.Check if each determinant is a candidate key.If a non-key determinant exists (common in denormalization), BCNF is violated.Mitigate risks using computed columns, triggers, or ETL checks.Document reasons and add indexes to support performance goals.

Verification / Alternative check:
Perform dependency analysis or use query-based profiling to detect anomalies (duplicates, inconsistent derived values) that indicate BCNF violation.

Why Other Options Are Wrong:
Surrogate keys and nullability do not guarantee BCNF. Declaring that denormalization “guarantees BCNF” reverses the definitions.

Common Pitfalls:
Assuming a surrogate key alone fixes normalization; ignoring referential checks after denormalization; failing to document which fields are duplicated and how to update them.

Final Answer:
Does not apply — denormalized tables typically violate BCNF