BYJU'S Interview Questions and Answers

Power BI has three connection modes: Import, DirectQuery, and Live Connection.

• Import mode imports data into Power BI and creates a dataset.

• DirectQuery mode connects to the data source and queries data in real-time.

• Live Connection mode connects to a published dataset in Power BI Service.

• Import mode is best for small to medium-sized datasets, while DirectQuery and Live Connection are better for large datasets.

• DirectQuery and Live Connection require a live connection to the data...read more

There are three types of gateways in Power BI: On-premises data gateway, Personal gateway, and Power BI Gateway (Enterprise). Each serves a different purpose.

• On-premises data gateway is used to connect on-premises data sources to Power BI service.

• Personal gateway is used for individuals to refresh data from on-premises data sources.

• Power BI Gateway (Enterprise) is used for organizations to manage data refresh for cloud and on-premises data sources.

• Gateways are used to securel...read more

I have used DAX time intelligence functions like TOTALYTD, SAMEPERIODLASTYEAR, etc.

• TOTALYTD function calculates the year-to-date total for a given expression

• SAMEPERIODLASTYEAR function returns the value of the same period in the previous year

• DATESYTD function returns a set of dates year-to-date based on the current context

Row level security in Power BI allows restricting data access based on user roles and filters.

• Row level security can be implemented using roles and filters in Power BI.

• Roles can be created and assigned to users or groups to restrict access to specific data.

• Filters can be applied to tables or columns to limit data visibility based on user roles.

• Row level security can be tested using the View As Roles feature in Power BI Desktop.

• Row level security can also be implemented using ...read more

Calculated columns are static values calculated at the row level, while measures are dynamic values calculated at the aggregate level.

• Calculated columns are stored in the data model and can be used in visuals directly.

• Measures are calculated on the fly based on the context of the visualization or report.

• Calculated columns are useful for creating new columns based on existing data, while measures are used for aggregations like sum, average, etc.

Cardinality in Power BI refers to the uniqueness of values in a column or relationship.

• Cardinality can be one-to-one, one-to-many, or many-to-many.

• It helps determine how data should be modeled and relationships should be established.

• For example, a one-to-many cardinality means one value in one table can be related to multiple values in another table.

SQL query to retrieve data from a table

• Use SELECT statement to specify columns to retrieve

• Use FROM statement to specify the table to retrieve data from

• Use WHERE statement to filter the data based on conditions