Week 5-6 Quiz on RDBS

What is the relational model primarily based on?

• Graph theory

• Set theory and predicate logic

• Hierarchical structure

• Network topology

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

• Primary key

• Superkey

• Unique key

• Cryptographic key

What is the main purpose of a foreign key?

• To uniquely identify rows in a table

• To enforce referential integrity between tables

• To act as a backup for the primary key

• To improve query performance

A table is in 1NF if:

• It has no repeating groups or arrays.

• All non-key attributes depend on the primary key.

• It has a primary key defined.

• It is free of transitive dependencies.

Which of the following violates the rules of 1NF?

• Having multiple attributes as part of a primary key

• Storing multiple values in a single attribute

• Using foreign keys to link tables

• Using derived attributes

A relation is in 2NF if:

• It is in 1NF and every non-prime attribute is fully functionally dependent on the primary key.

• It has no partial dependencies.

• It has no transitive dependencies.

• It is in 3NF.

A candidate key is:

• A subset of attributes that can uniquely identify a row but is not the primary key.

• A foreign key used in relationships.

• A derived attribute.

• A redundant attribute.

What is the purpose of normalization?

• To create redundant data for performance optimization.

• To minimize data redundancy and eliminate anomalies.

• To create foreign key relationships.

• To improve indexing.

Which normal form ensures there are no transitive dependencies?

• 1NF

• 2NF

• 3NF

• BCNF

What is a transitive dependency?

• When a non-prime attribute depends on a prime attribute.

• When a non-prime attribute depends on another non-prime attribute.

• When a primary key is dependent on a foreign key.

• When multiple attributes form a composite key.