Ch3 Relational Database Model Quiz 4

What is the primary purpose of a relational database model?

• To store data physically

• To organize data logically

• To manage network connections

• To encrypt data

In a relational database, a table is also referred to as a:

• Domain

• Relation

• Entity

• Attribute

Which of the following best describes a primary key?

• A value used to encrypt data

• An attribute that must be null

• A unique identifier for each row in a table

• A key used to search for data

What is a domain in a relational database?

• The total number of rows in a table

• The set of permissible values for an attribute

• The name of the database

• The relationship between two tables

Which type of key is composed of more than one attribute?

• Candidate key

• Superkey

• Composite key

• Primary key

What does a foreign key in a relational database do?

• It uniquely identifies a row within a table

• It links tables by referencing the primary key of another table

• It enforces domain integrity

• It provides backup for the primary key

In relational algebra, which operator is used to combine two tables by dropping duplicate rows?

• INTERSECT

• UNION

• DIFFERENCE

• PRODUCT

What does the SELECT operator in relational algebra do?

• Selects a subset of columns

• Selects a subset of rows

• Joins two tables

• Creates a new table

Referential integrity ensures:

• Foreign keys are unique in their table

• Foreign key entries must have matching primary key entries

• All data is encrypted

• The data types of two tables are compatible

Which of the following is a minimal superkey?

• Composite key

• Candidate key

• Foreign key

• Secondary key