What is Denormalization? — Learn free

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Questions 1–10 of 10

1. What is Denormalisation?
Question 1A. The deliberate process of combining tables or reintroducing controlled redundancy to improve query performance and analytical usabilityB. A careless shortcut that skips data modellingC. The process of removing all redundancy from tablesD. The process of converting tables to 6NFE. The process of encrypting reporting data
2. What is the core idea behind denormalisation?
Question 2A. Data should never be normalised in the first placeB. All tables should be split into single-attribute tablesC. Once data is properly structured, typically to 3NF or BCNF, certain tables may be merged or attributes duplicated to reduce joinsD. Redundancy should be eliminated at all costsE. Every query should use as many joins as possible
3. Which of the following is a typical denormalisation technique?
Question 3A. Pre-calculating derived valuesB. Removing foreign keys entirelyC. Splitting a table into many smaller tablesD. Adding a new column each monthE. Deleting descriptive attributes
4. In which environments are the benefits of denormalisation especially visible?
Question 4A. OLTP systems with frequent updatesB. Source systems with heavy write loadsC. Message queuesD. BI and OLAP environmentsE. Version control systems
5. Which modelling techniques have denormalisation as their structural foundation?
Question 5A. Data Vault and Anchor ModellingB. NIAM, ORM and FCO-IMC. Star schemas, snowflake schemas and Unified Star Schema designsD. BPMN and DDDE. Taxonomies and ontologies
6. Which of the following is NOT a trade-off of denormalisation?
Question 6A. Redundancy is reintroducedB. Updates must be carefully managed to avoid inconsistenciesC. Storage requirements increaseD. Queries require more joinsE. Maintenance challenges in transactional systems
7. In the loan example, what fields might a denormalised LoanFact table contain?
Question 7A. Only LoanID and CustIDB. Only the primary keys of each source tableC. Server name and partition keyD. Only the ApprovalStatusE. CustomerName, LoanAmount, ProductType, ApprovalStatus, RepaymentDueDate and RepaymentStatus
8. What redundancy appears in the denormalised LoanFact example?
Question 8A. LoanID appears once per customerB. Each repayment is stored in its own tableC. ApprovalStatus is stored in a separate lookupD. There is no redundancyE. CustomerName may appear repeatedly across many rows
9. How does denormalisation relate to normalisation?
Question 9A. It replaces normalisationB. It builds upon normalisation, assuming the logical structure has already been validatedC. It must be done before normalisationD. It is unrelated to normalisationE. It reverses 1NF only
10. In the modelling journey, what roles do normalisation and denormalisation respectively play at the hinge point?
Question 10A. Normalisation enhances performance; denormalisation protects integrityB. Normalisation protects integrity; denormalisation enhances usability and performanceC. Both protect integrity equallyD. Both are concerned only with storage costE. Normalisation is for OLAP; denormalisation is for OLTP