1.3.2a Database design: keys, entity relationships, normalisation and indexing Quiz: OCR Computer Science, Unit 3

The 20 questions

1. What attribute uniquely identifies a record in a relational database table?

   • Foreign key
   • Candidate key
   • Composite key
   • Primary key

2. Which normal form requires the removal of repeating groups or non-atomic attributes?

   • Boyce-Codd normal form
   • Third normal form
   • Second normal form
   • First normal form

3. Which normal form eliminates partial dependencies on a composite primary key?

   • Unnormalised form
   • Second normal form
   • First normal form
   • Third normal form

4. Which database normal form removes non-key attributes that depend on other non-key attributes?

   • Fourth normal form
   • Third normal form
   • Second normal form
   • First normal form

5. What key links a record in one table to the primary key in another?

   • Surrogate key
   • Foreign key
   • Primary key
   • Candidate key

6. What consists of two or more attributes that together uniquely identify a row?

   • Surrogate key
   • Composite key
   • Secondary key
   • Foreign key

7. What data structure technique is used to speed up data retrieval operations on a table?

   • Indexing
   • Encapsulation
   • Aggregation
   • Normalisation

8. Which relationship type cannot be directly implemented in a relational database without a junction table?

   • Many-to-one
   • Many-to-many
   • One-to-one
   • One-to-many

9. An attribute depends on only part of a composite primary key. Which normal form is violated?

   • Second normal form
   • First normal form
   • Fourth normal form
   • Third normal form

10. An attribute depends on another non-key attribute instead of the primary key. Which normal form is violated?

    • First normal form
    • Third normal form
    • Second normal form
    • Unnormalised form

11. To represent a doctor treating many patients, and patients seeing many doctors, what table structure is required?

    • Index table
    • Foreign table
    • Composite table
    • Junction table

12. A database field contains a comma-separated list of multiple telephone numbers. Which normal form does this violate?

    • Second normal form
    • Third normal form
    • Boyce-Codd normal form
    • First normal form

13. What is a major operational disadvantage of having multiple indexes on a frequently updated database table?

    • Larger schema
    • Slower inserts
    • Broken relationships
    • Higher latency reads

14. Where should the foreign key be placed when implementing a one-to-many relationship between Department and Employee?

    • Both tables
    • Employee table
    • Department table
    • Junction table

15. What database rule prevents a foreign key from referencing a non-existent primary key value in another table?

    • Entity integrity
    • Domain integrity
    • Referential integrity
    • Transitive integrity

16. If attribute X uniquely determines attribute Y, how is this functional dependency written in database notation?

    • Y -> X
    • X -> Y
    • X = Y
    • Y <-> X

17. An automatically generated unique identifier with no real-world business meaning is known as what type of key?

    • Natural key
    • Surrogate key
    • Candidate key
    • Secondary key

18. Any attribute or combination of attributes that could uniquely identify a database row is called what?

    • Candidate key
    • Secondary key
    • Surrogate key
    • Foreign key

19. What term describes accidentally losing essential information when removing a record from an unnormalised database?

    • Transitive anomaly
    • Insertion anomaly
    • Deletion anomaly
    • Update anomaly

20. What relationship cardinality exists between a UK citizen and their unique National Insurance number?

    • Many-to-many
    • Many-to-one
    • One-to-one
    • One-to-many

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