Data Engineering Data Modeling and Schema Design 2

Question 1

Which normal form requires that every non-key attribute is fully functionally dependent on the entire primary key, not just part of it?

Accepted Answer

Second Normal Form (2NF)

Answer

2NF eliminates partial dependencies, requiring every non-key attribute to depend on the whole composite primary key.

Question 2

A fact table with very few numeric measures that primarily stores the occurrence of an event is called a:

Accepted Answer

Factless fact table

Answer

A factless fact table records events or coverage relationships without any numeric measures, only keys to dimension tables.

Question 3

What is the purpose of a 'junk dimension' in dimensional modeling?

Accepted Answer

To combine multiple low-cardinality flags and indicators into a single dimension

Answer

A junk dimension consolidates miscellaneous low-cardinality flags and indicator fields into one dimension to reduce fact table width.

Question 4

In the Kimball methodology, what is the 'Bus Matrix' used for?

Accepted Answer

Mapping which business processes share which conformed dimensions

Answer

The Enterprise Bus Matrix maps each business process (fact table) against the dimensions it shares, ensuring conformed dimensions across the data warehouse.

Question 5

Which schema type is most appropriate when querying across multiple star schemas that share common dimensions?

Accepted Answer

Galaxy schema (fact constellation)

Answer

A galaxy schema (fact constellation) consists of multiple fact tables sharing conformed dimension tables, enabling cross-subject-area queries.

Data Engineering Practice Test

Data Engineering Practice Test

Data Engineering Data Modeling and Schema Design 2