10+ Senior Power BI Developer Interview Questions and Answers

Optimizing slow-performing Power BI reports requires various strategies.

• Identify and remove unnecessary visuals or data

• Optimize DAX calculations and queries

• Reduce the number of visuals on a single page

• Use aggregations and summary tables for large datasets

• Consider using DirectQuery mode for real-time data

• Use query folding to push data transformation operations to the data source

The question involves finding the output of a table, ways to find max and second max in SQL, row level security on column, and index in details.

• To find the output of the table, you need to analyze the pattern of the data and count the occurrences of each value for each letter.

• To find the max and second max in SQL, you can use the MAX() function with ORDER BY and LIMIT clauses, or use a subquery to find the second highest value.

• Row level security on a column can be implemented...read more

RLS restricts data access based on user roles, ensuring users only see relevant data.

• RLS filters data based on user's role or attributes

• It limits access to rows in a table based on user's role

• Users can only see data that they have permission to access

Nulls in data sets are handled by filtering them out, replacing them with default values, or using functions like COALESCE.

• Filter out null values using WHERE clause in SQL queries

• Replace null values with default values using COALESCE function in SQL

• Use IFNULL function in MySQL to handle null values

• Handle null values in Power BI by using DAX functions like ISBLANK and IF

Data governance in Power BI involves establishing policies, processes, and controls to ensure data quality, security, and compliance.

• Establish data quality standards and guidelines for data sources

• Implement role-based access control to restrict access to sensitive data

• Monitor data usage and track changes to ensure compliance with regulations

• Create data lineage documentation to track the flow of data from source to report

Star schema has a single fact table connected to multiple dimension tables, while snowflake schema has normalized dimension tables.

• Star schema denormalizes data for faster query performance.

• Snowflake schema normalizes data to reduce redundancy and improve data integrity.

• Star schema is easier to understand and query, but snowflake schema is more flexible and scalable.

• Example: A star schema for a sales database would have a fact table for sales transactions connected to dimensi...read more

Truboolshot is not a recognized term in Power BI; it may be a misspelling or confusion with another concept.

• Possible Misspelling: It could be a misspelling of 'troubleshoot', which refers to diagnosing and resolving issues in Power BI reports.

• Troubleshooting Techniques: Common troubleshooting techniques in Power BI include checking data sources, validating DAX formulas, and reviewing visualizations.

• Performance Optimization: Troubleshooting may also involve optimizing report p...read more

Data modeling involves structuring and organizing data to make it easier to analyze and visualize in Power BI.

• Identify the key business questions and goals to determine what data needs to be collected and analyzed.

• Normalize data to reduce redundancy and improve data integrity.

• Create relationships between different data tables to enable accurate analysis and visualization.

• Use data modeling techniques such as star schema or snowflake schema to optimize performance.

• Utilize DAX c...read more

Best practices for data modelling

• Understand the business requirements before designing the data model

• Normalize data to reduce redundancy and improve data integrity

• Use surrogate keys for better performance and scalability

• Avoid complex relationships and keep the model simple and easy to understand

• Regularly review and optimize the data model for efficiency

Direct query connects to data source in real-time, while import loads data into Power BI for faster analysis.

• Direct query retrieves data from source on-demand, ensuring real-time data accuracy.

• Import loads data into Power BI for faster analysis, but may not reflect real-time changes.

• Direct query is suitable for large datasets that require up-to-date information.

• Import is ideal for smaller datasets or when real-time data is not necessary.

Power BI is a business analytics tool by Microsoft that provides interactive visualizations and business intelligence capabilities.

• Power BI is a business analytics tool by Microsoft

• It allows users to create interactive visualizations and reports

• Users can connect to various data sources to gather insights

• Power BI offers a wide range of data visualization options such as charts, graphs, and maps