Supertype and Subtype — Learn free

Self-check

Questions 1–10 of 10

1. In data modelling, what is a supertype?
Question 1A. A generalisation representing a higher-level entity that contains attributes common to multiple related entitiesB. A table that stores only numeric factsC. A specialised entity with attributes unique to itselfD. A database index that speeds up queriesE. A primary key shared by two tables
2. In data modelling, what is a subtype?
Question 2A. A backup copy of a supertypeB. A specialisation of a supertype, representing a more specific entity that inherits attributes and may add its ownC. A column that stores datesD. A view that hides sensitive dataE. A generalisation of several unrelated entities
3. In the Vehicle example, which attributes belong to the supertype?
Question 3A. Number of Doors and Body TypeB. Department and SkillsC. Manufacturer, Model and YearD. Name and EmployeeIDE. Engine Size and Fuel Type
4. In the Vehicle example, which attributes might the Car subtype add beyond those it inherits?
Question 4A. Manufacturer and ModelB. Year and Registration CountryC. Name and EmployeeIDD. Number of Doors and Body TypeE. Budget and Expenditure
5. What benefit does inheritance provide when subtypes inherit attributes from a supertype?
Question 5A. Faster network transferB. Stronger encryptionC. Smaller server hardwareD. Automatic data cleansingE. Reusability and reduced redundancy
6. What does completeness describe in the supertype and subtype relationship?
Question 6A. Whether subtypes are total, covering all instances of the supertype, or partial, covering only someB. Whether all columns have been filled inC. Whether the database has been backed upD. Whether every table has a primary keyE. Whether the model has been reviewed by an auditor
7. In the Employee example, which are the subtypes?
Question 7A. Name and EmployeeIDB. Manager and TechnicianC. Department and SkillsD. Vehicle and CarE. Admissions and Finance
8. Which pairing correctly matches the modelling terms with their roles?
Question 8A. Supertype represents specialisation, subtype represents generalisationB. Both supertype and subtype represent generalisationC. Supertype represents generalisation, subtype represents specialisationD. Both supertype and subtype represent specialisationE. Neither term relates to generalisation or specialisation
9. Which of the following is NOT true of a subtype?
Question 9A. It inherits attributes from its supertypeB. It may have additional attributes of its ownC. It represents a more specific category within the generalisationD. It contains only the attributes shared by all related entities and no othersE. It can be total or partial in coverage
10. In summary, why are supertypes and subtypes used in data modelling?
Question 10A. To reduce the number of tables to exactly oneB. To encrypt sensitive attributesC. To speed up batch processingD. To convert relational data into documentsE. To represent general and specific entities, capturing both commonalities and differences among related entities