In RDBMS, different classes of relations are created using __________…

Correct answer: Normal Forms

Why: Normalization organizes relations into normal forms to remove redundancy and prevent modification anomalies (insertion, update, deletion).

• Insertion anomaly: difficulty adding data without spurious or missing values.

• Update anomaly: redundant copies of data lead to inconsistent updates if not all copies are changed.

• Deletion anomaly: removing a tuple may unintentionally lose other valid information.

How normal forms help:

• 1NF (First Normal Form): Eliminates repeating groups; ensures atomic attribute values.

• 2NF (Second Normal Form): Removes partial dependencies on a composite key by decomposing relations.

• 3NF (Third Normal Form) and BCNF: Remove transitive and other non-key dependencies to further reduce redundancy.

Note: Functional dependencies are used to detect which decompositions are needed when applying normal forms, but the named technique that creates relation classes to avoid modification anomalies is normalization into normal forms.

Practical steps:

• Identify functional dependencies in the relation.

• Decompose the relation into smaller relations that satisfy higher normal forms while preserving dependencies and ensuring lossless join.

• Verify that the decomposed relations eliminate the observed insertion, update, and deletion anomalies.