Data Architecture and Modeling Flashcards

In a snowflake schema, how do dimension tables differ from those in a star schema?

Answer: They are normalized into multiple related tables rather than a single denormalized table

In a snowflake schema, dimension tables are normalized into multiple related sub-tables, reducing redundancy compared to the denormalized dimension tables in a star schema.

What is a Slowly Changing Dimension (SCD) Type 2?

Answer: A dimension that tracks history by adding new rows with effective date ranges when attributes change

SCD Type 2 tracks historical changes by adding new rows with start/end dates, allowing analysis of both current and historical dimension attribute values.

Which data architecture style uses a central repository where raw data is stored in its native format until needed?

Answer: Data Lake

A Data Lake stores raw data in its native format at scale, allowing flexible analysis later, unlike data warehouses that require structure upfront.

What is a conceptual data model?

Answer: A high-level representation of business concepts and relationships without technical detail

A conceptual data model provides a high-level, business-focused representation of key entities and relationships without technical implementation details.

In data modeling, what does cardinality describe?

Answer: The numerical relationship between instances of two entities (e.g., one-to-many)

Cardinality describes the quantitative relationship between entity instances, such as one-to-one, one-to-many, or many-to-many relationships.

What is the primary advantage of a Data Vault modeling approach over traditional star/snowflake schemas?

Answer: Better auditability, flexibility for change, and support for loading from multiple source systems

Data Vault modeling excels at auditability, handles source system changes gracefully, and supports parallel loading from multiple sources using its Hub-Satellite-Link structure.