Microsoft Certified Data Analyst Associate Power BI Data Modeling 1 — Questions and Answers
Question 1: Which relationship cardinality type is most commonly used between fact tables and dimension tables in a star schema?
- One-to-one
- Many-to-many
- One-to-many (Correct answer)
- Many-to-one
Correct answer: One-to-many
One-to-many relationships are the standard in star schema designs, where one dimension record relates to many fact records.
Question 2: What is the purpose of setting a column as a 'Key Column' in a Power BI table?
- To sort the table alphabetically
- To uniquely identify each row in the table (Correct answer)
- To create a relationship automatically
- To hide the column from reports
Correct answer: To uniquely identify each row in the table
Marking a column as a Key Column indicates it uniquely identifies each row, which is important for data integrity and relationships.
Question 3: In Power BI, what does a bidirectional cross-filter do in a relationship?
- It prevents filters from crossing the relationship
- It allows filters to flow in both directions between tables (Correct answer)
- It creates a many-to-many relationship automatically
- It improves query performance
Correct answer: It allows filters to flow in both directions between tables
Bidirectional cross-filtering allows filter context to propagate in both directions across a relationship, enabling more flexible slicing.
Question 4: What is a calculated column in Power BI?
- A column computed at query time using M code
- A column added to a table using a DAX formula evaluated row by row (Correct answer)
- A column imported from a SQL view
- A column created by merging two existing columns
Correct answer: A column added to a table using a DAX formula evaluated row by row
Calculated columns are defined with DAX and are computed row by row during data refresh, storing results in the model.
Question 5: Which storage mode stores data in the Power BI model and does NOT query the source on every interaction?
- DirectQuery
- Live Connection
- Import (Correct answer)
- Composite
Correct answer: Import
Import mode loads data into Power BI's in-memory engine, so all queries run against the cached dataset without hitting the source.
Question 6: What is the role of a 'Role-Playing Dimension' in a Power BI data model?
- A dimension used only for row-level security
- A single dimension table referenced multiple times via inactive relationships for different date contexts (Correct answer)
- A dimension shared across multiple datasets
- A table with multiple primary keys
Correct answer: A single dimension table referenced multiple times via inactive relationships for different date contexts
Role-playing dimensions allow a single dimension (like Date) to serve multiple roles (e.g., Order Date, Ship Date) using inactive relationships activated by USERELATIONSHIP.
Microsoft Certified Data Analyst Associate Power BI Data Modeling 1
Which relationship cardinality type is most commonly used between fact tables and dimension tables in a star schema?