PL-300: Microsoft Power BI Data Analyst
You preview a single table into Power Query Editor in Power BI Desktop. The table contains the following columns: LocationName, LocationID, Temperature, and DateTime.
You need to convert the table into a properly formed star schema.
To which table should you add the LocationName field?
Temperature Measurements Fact
Date Dimension
Location Dimension
Location Fact
You have a Power BI model that contains sensor data from 500 sensors that return temperature readings each minute.
Your reporting requirements contain the need to calculate the average temperature from each sensor at every hour. The reports do NOT show the raw data for each minute.
You need to reduce the size of the model to improve performance.
What should you do?
Create visuals that group the data by hour.
Use Power Query to group the sensor data by hour.
And a report filter for the Hour column.
Remove the rows that contain readings.
The two types of tables in a star schema are what?
Active and inactive tables
Qualitative and quantitative data tables
Fact and dimension tables
Answer is Fact and dimension tables
What is the difference between a fact table and a dimension table?
Fact tables store observations or events while dimension tables contain information about specific entities within the data
Fact tables contain information about specific entities while dimension tables contain information about observational data
Dimension tables tell you about specific roles in Power BI while fact tables tell you information about facts that are associated with those roles in Power BI
There is no difference
Answer is Fact tables store observations or events while dimension tables contain information about specific entities within the data
What is Cardinality?
Cardinality is how long it takes for the data to load
Cardinality is the granularity of the data
The direction that the data flows in a relationship between two tables
Cardinality is a type of visual element
Answer is The direction that the data flows in a relationship between two tables
What is it called when multiple records in one table are associated with multiple records in another table?
many-to-many relationship
one-to-many relationship
many-to-one relationship
Answer is many-to-many relationship
A dimension that can filter related facts differently is called what?
Role-playing dimension
Snowflake dimension
Degenerate dimension
Answer is Role-playing dimension
What type of table stores details about business entities?
Fact table
Dimension table
Date table
Data table
Answer is Dimension table
You are creating a quick measure as shown in the following exhibit.
You need to create a monthly rolling average measure for Sales over time.
How should you configure the quick measure calculation?
Box 1: Total Sales
We select the field Total Sales
Box 2: Date
Select a date field.
Box 3: Month
Monthly periods.
Reference:
https://docs.microsoft.com/en-us/power-bi/transform-model/desktop-quick-measures
You have sales data in a star schema that contains four tables named Sales, Customer, Date, and Product. The Sales table contains purchase and ship dates.
Most often, you will use the purchase date to analyze the data, but you will analyze the data by both dates independently and together.
You need to design an imported dataset to support the analysis. The solution must minimize the model size and the number of queries against the data source.
Which data modeling design should you use?
Use the Auto Date/Time functionality in Microsoft Power BI and do NOT import the Date table.
Duplicate the Date query in Power Query and use active relationships between both Date tables.
On the Date table, use a reference query in Power Query and create active relationships between Sales and both Date tables in the modeling view.
Create an active relationship between Sales and Date for the purchase date and an inactive relationship for the ship date.
Answer is Create an active relationship between Sales and Date for the purchase date and an inactive relationship for the ship date.
Only one relationship can be active.
Note: If you query two or more tables at the same time, when the data is loaded, Power BI Desktop attempts to find and create relationships for you. The relationship options Cardinality, Cross filter direction, and Make this relationship active are automatically set.
Reference:
https://docs.microsoft.com/en-us/power-bi/transform-model/desktop-create-and-manage-relationships