Quiz on the Relational Model

Who first introduced the relational model?

• E. F. Codd

• Jim Gray

• C. J. Date

• Michael Stonebraker

What is a relation in the context of the relational model?

• A table with columns and rows

• A type of database

• A programming language

• A set of rules

What does the term 'cardinality' refer to in a relation?

• The number of tuples

• The order of attributes

• The uniqueness of tuples

• The number of attributes

Which of the following is a property of relations?

• Attributes can have duplicate names

• Order of tuples is significant

• Tuples can be identical

• Each cell contains exactly one atomic value

What is a primary key?

• A candidate key selected to identify tuples uniquely

• A key that can identify any row

• A key used for data retrieval

• A key that can be null

What does referential integrity ensure?

• All keys are unique

• All attributes must be defined

• Foreign key values must match candidate key values

• No null values in the database

What is the purpose of views in a relational database?

• To delete data

• To provide a security mechanism

• To permanently store data

• To create new tables

Which of the following is NOT a type of key in the relational model?

• Foreign key

• Primary key

• Secondary key

• Tertiary key

What is entity integrity?

• Attributes must have defined domains

• All values in a primary key must be unique

• No attribute of a primary key can be null

• All tuples must be distinct

What is a foreign key?

• A key that can be null

• A key that identifies a row in the same table

• A key used for indexing

• A primary key from another table