Test: Quiz: Entities, Instances, Attributes and Identifiers

Section 1

1. What is the purpose of a Unique Identifier? Mark for Review
(1) Points

To uniquely determine a table and columns within that table.

To identify a specific row within a table, using one or more columns and/or foreign keys.

Create an entity that is unlike any other entity aside from itself.

To identify one unique instance of an entity, by using one or more attributes and/or relationships. (*)





2. Some of the following could be attributes of an ENTITY called PERSON. Select the incorrect attributes for PERSON. (Choose Two) Mark for Review
(1) Points

(Choose all correct answers)

Age

Freddy Wilson (*)

Name

Priya Hansenna (*)





3. Which of the following statements about attributes are true? (Choose Two) Mark for Review
(1) Points

(Choose all correct answers)

They describe, qualify, quantify, classify, or specify an entity. (*)

They are often adjectives.

They have a data type such as a number or character string. (*)

They must be single valued unless they belong to more than one entity.





4. Unique Identifiers.... Mark for Review
(1) Points

distinguish one entity from another

distinguish one instance of an entity from all other instances of that entity (*)

distinguish all entities in a database

distinguishes nothing





5. In the following statements, find two examples of ENTITY: Instance. (Choose Two) Mark for Review
(1) Points

(Choose all correct answers)

DAIRY PRODUCT: cow (*)

VEGETABLE: grows

BOOK: Biography of Mahatma Gandhi (*)

TRAIN: runs





6. An entity may have which of the following? Mark for Review
(1) Points

experiences

instances (*)

tables

none of the above





7. Entities are usually verbs. True or False? Mark for Review
(1) Points

True

False (*)





8. A/an _________ is a piece of information that in some way describes an entity. It is a property of the entity and it quantifies, qualifies, classifies or specifies the entity. Mark for Review
(1) Points

ERD

Process

Table

Attribute (*)





9. All of the following would be instances of the entity PERSON except which? Mark for Review
(1) Points

David Jones

Male (*)

Angelina Rosalie

Grace Abinajam





10. Which of the following entities most likely contains invalid attributes? Mark for Review
(1) Points

Entity: Home. Attributes: Number of Bedrooms, Owner, Address, Date Built

Entity: Pet. Attributes: Name, Birthdate, Owner

Entity: Car. Attributes: Owner Occupation, Owner Salary, Speed (*)

Entity: Mother. Attributes: Name, Birthdate, Occupation, Salary





11. In a physical data model, an attribute is represented as a/an Mark for Review
(1) Points

Column (*)

Row

Instance

Foreign Key





12. The word "Volatile" means.... Mark for Review
(1) Points

Changing constantly; unstable (*)

Static; unlikely to change

Large quantity

Limited quantity