Data Modeling and Analysis

Correct Answer: Creating a Type 2 dimension where historical records are preserved by adding new rows

Creating a Type 2 dimension where historical records are preserved by adding new rows is the most commonly used and effective approach for handling slowly changing dimensions (SCD) in dimensional modeling. This method allows organizations to: - Track historical changes over time - Maintain data lineage - Support accurate historical reporting - Preserve the complete history of dimensional attributes The other options are less suitable because: - Type 4 dimensions are rarely used and add unnecessary complexity to the data model - A hybrid approach combining fact table versioning and dimensional overwriting creates additional overhead and complexity - Adding timestamps to fact tables while maintaining single version dimensions fails to capture historical changes in dimensional attributes effectively Type 2 SCD is considered an industry standard practice, especially when historical accuracy and tracking changes over time are crucial requirements for business intelligence and reporting.

Correct Answer: A central fact table connected to multiple dimension tables

In dimensional modeling, a star schema is characterized by a central fact table that is connected to multiple dimension tables in a hub-and-spoke arrangement. The correct answer describes this exact structure - a central fact table connected to multiple dimension tables. This arrangement creates the star-like pattern that gives the schema its name. Other options are incorrect because: - A series of interconnected dimension tables would be more characteristic of a snowflake schema, where dimensions are normalized - Having multiple fact tables linked to a single dimension table would be the opposite of a star schema's structure - A complex network of normalized tables with recursive relationships describes a highly normalized relational database structure, not a dimensional model like star schema which is purposely denormalized for analytical queries

Correct Answer: A shared dimension that maintains consistent values across multiple fact tables

A conformed dimension is a critical concept in dimensional modeling that represents a shared, standardized dimension used consistently across multiple fact tables in a data warehouse. The correct answer describes the fundamental characteristic of a conformed dimension: it maintains consistent values across multiple fact tables. This ensures data consistency, enables cross-fact table analysis, and supports enterprise-wide reporting. The other options are incorrect because: - Transforming attribute values based on business requirements describes a general dimension transformation process, not specifically a conformed dimension - Maintaining separate instances of attributes for each fact table is the opposite of conformity and would lead to inconsistency - Applying unique transformation rules to each fact table relationship would create inconsistencies, which defeats the purpose of dimension conformity Conformed dimensions are essential for maintaining data consistency and enabling integrated analysis across different business processes in a data warehouse environment.