If you’re seeking to make a career in web development, there’s every chance that you will encounter Power BI interview questions. Among the flurry of technological advancements, the demand for data reporting and data visualizations is increasingly soaring. As a result, developers are continually vying for options to make their data reports the most comprehensive and graphic.

Some of the key players in the field of software technology consistently try to develop advanced solutions for data reporting. It is in that context that self-service BI or business intelligence (SSBI) was conceived. This enabled any standard user to utilize the available templates and data analytics features to transform data and make accurate reports visually. Among the other SSBI tools, Microsoft’s Power BI has emerged one of the most widely used tools.

Following its initial release between 2013 and 2015, Microsoft PowerBI has made itself relevant in major business intelligence operations. This has earned the tool a seat in Garnter’s Magic Quadrant as one of the most important tools for IT firms, especially in the area of business analytics.

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Microsoft has gained a significant market share with its simplified Power BI data visualization and data reporting tools. Power BI is an amalgamation of separate entities that Microsoft has clubbed together to enhance the business intelligence experience. Each of the tools come together to create a BI infrastructure. So businesses may pick and choose the tools that pertain to their business goals the most while making the most of the boons of Power BI.

Given the popularity of PowerBI, Power BI interview questions are not only hard to avoid but also essential to build your acumen inefficient data representation. Whether as a beginner, an intermediate or an advanced user of PowerBI searching for powerbi jobs, there are certain questions that you are sure to encounter in your interview.

Below we have discussed some of the frequently asked Power BI interview questions and answers.

Top Power BI Interview Questions & Answers

Several users have mastered their way around the PowerBI tool but may not be able to articulate in words what exactly the tool is and the different functions associated with it. That is what this guide is for. Therefore, we will begin from the basic Power BI interview questions for freshers and then move on to the advanced Power BI scenario based interview questions and answers.

1. What is Power BI and how does it work?

Power BI is a Microsoft Business Analytics tool with a body of processes and technologies that make it easier for businesses to derive information from raw data sources. With PowerBI, analytics teams are able to make connections between related and unrelated data, transform the data and perform visualizations that are relevant and understandable by others in the organization. This data can be in different formats such as spreadsheet, cloud-based or on-set.

2. What are the critical characteristics of Power BI?

At the very outset Power, BI is a set of tools that can help enterprises to collect data and promptly convert the data collected into visual reports and share them as well with the desired recipients. Users can also choose to view, search, and analyze data on any given area in one go.

The security and regulation features of Power BI are so advanced that enterprises can choose to scale up their data reports using Power BI. The shareability feature of Power BI reports enables enterprises to share and view the reports on multiple platforms at the same time. Power BI also includes a natural language processor which allows the users to get assistance. 

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3. What are the different versions of Power BI available?

The complete package of Power BI comprises a variety of tools, which in turn facilitates flexibility of use. In that regard, enterprises may choose to use only the version of Power BI that seems the most relevant to their use. Three of the most popularly available versions are :

• Power BI for Desktop – As can be understood from the name, this version is best suited for those using Windows 10 and higher configurations of desktop operating systems.
• Power BI Service -This version is helpful to launch and share the data reports through the cloud.
• Power BI for mobile – As explained from the name, this version is best for use on mobile phones. 

4. Explain the five major components of Power BI

Power BI includes five major components.

• Power Pivot-Collects data and transmutes the relevant information to the query.
• Power Query- This is where the data loaded is analyzed and operated on.
• Power Q&A-Reports are made interactive using this feature. Users can engage with the findings of the reports using simple English words. 
• Power View-This component further enhances the dynamic attribute of Power BI. Users can further visualize their reports using interactive maps, graphs, and charts. 
• Power Map-This component processes the geographic locations in the datasets.

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5. What are the different data filters available in Power BI?

The data loaded on Power BI may be filtered through the three prominent filters. 

• Drillthrough Filters – Through this filter, users are able to create a specific page in their reports, which emphasize on a particular entity.
• Page-level Filters – Page-level Filters enable users to filter out specific information in particular pages. 
• Report level filters – This filter assists in filtering out particular data in the entire report. 

6. How does Power BI store data?

Once data is loaded in Power BI, it is stored in two forms of tables.

• Fact Tables – This is the storehouse of quantitative data. On most occasions, these aren’t normalized. 
• Dimension Tables – These stores more qualitative information. They contain the attributes and dimensions of the data in the fact tables. 

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7. What are the important tools of Power BI?

• The Query Editor – All the gathering and transformation of data in Power BI is done through the Query Editor. It is also referred to as the Power Query. Query Editor extracts data from different locations and also converts it into forms that are more suited to analysis. Query Editor is adept at collecting data from a variety of sources ranging from text and Excel charts to social media platforms like Facebook.
• Once the data is extracted, the query editor converts the data into a more conducive form through a specific process. First, the information is split into multiple columns, then pivoting and unpivoting is followed, thereafter, the data types are modified. Finally, the data from the different extractions are merged into a single table. 
• The xVelocity In-memory Analytical Engine – The The technology responsible for the actual storage and retrieval of data within Power BI is called xVelocity In-memory Analytical Engine. It is often referred to by its shorter name, vertiPaq engine. It stores the aggregated data in the memory, which is then made available for querying.
• By using an advanced data compression algorithm, the vertiPaq engine is able to hold a large amount of data in the memory. To enhance the speed of processing and compressing data, it operates as a columnar store wherein the data is organized along columns of tables rather than rows, as in the case of traditional data tables. 
• The Tabular Model – Power BI uses the tabular data model to define the relationships and hierarchies between the data tables. For making business calculations, the tabular model uses measures. Measures perform a wide range of calculations from the simple sum of a set of data to a more complex deduction of a percentage of growth etc. Data Analysis Expressions, or DAX, are used to define measures. 
• Power View – Power View is the tool that is responsible for data visualization in Power BI. The interactive and dynamic features of a Power BI report and dashboards are majorly attributed to Power View. 

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8. What do you mean by DAX? How does using variables benefit DAX?

Data Analysis Expressions or DAX essentially define measures that are used to make calculations in Power BI. It is helpful for querying and returning data by table expression. As a formula language, DAX performs data calculations and analysis. Alongside measures, DAX also computes data and fields. 

Using variables can make DAX work smoothly. Not only can variables be reused in the Query Editor, but it also helps in avoiding any additional queries in the source databases. It is with the help of variables that we can understand the DAX expressions. 

Learn More: Business Analytics: Tools, Applications & Benefits

9. What do you mean by Power BI service?

Power BI service is what makes Power BI accessible to the users. It is a cloud-based portal through which the Power BI content can be shared. Most of the Power BI service features are free for use at PowerBI.com. However, more exclusive and accentuated features for organization-level sharing of content can be availed through Power BI Premium Licensing or Power BI Pro. 

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10. What is the Power BI Report Server?

Often the content generated by enterprises on Power BI includes classified and confidential data. As a result, enterprises are wary of releasing such content in the cloud, even for the purpose of sharing. To resolve this issue Power BI report server lets you share the content through the authentication method using SQL instead of a cloud platform.

Power BI report server is a SQL server reporting service that can manage Power BI reports and authenticate the content to be shared. Power BI report server is only available with Power BI Pro or Power BI Premium Licensing. 

11. Can Power BI be used on mobiles?

While both the Power BI service and Power BI report server can be accessed through any browser both on desktop or on mobiles, there are mobile-optimized Power BI apps available as well.

There are Power BI apps compatible with Windows, Android, and iOS devices, which enable users to connect to Power BI service as well as Power BI report server on their smartphones and even tablets and iPads. 

12. What are the content packs in Power BI?

Simply put, content packs include the collection of reports, datasets, and dashboards that are generated using a Power BI service, and that can be shared with other Power BI users. Content Packs give specific people, and organizations access to the Power BI reports and datasets.

The packs can be customized with labels that can help users identify the content precisely. People with access to the content pack can use the content from the packs to create new dashboards. 

13. Are there any security features available on Power BI?

Power BI uses Row-level Security for its reports and dashboards. Along with the filters, the row-level security restricts access to Power BI reports and other content. In this feature, users can regulate the rules of access and publish the same using Power BI Service.

Row-level security also includes specific functions to monitor the access of current users to appropriate content. However, Row-level security is only available on premium Power BI subscriptions. 

14. Describe the Gather function of the Power BI process

The Gather function in Power BI collects and transforms data. As with the case of Query Editor, the data is gathered using the Gather function from multiple sources and stored in a single location. This facilitates smooth and prompt data analysis.

Following the collection, the data is transformed, which necessarily entails the removal of errors and any inconsistency. The end product of this process is clean data, which is aligned with the rest of the data stores in Power BI. 

15. What role does the Store Function perform in Power BI?

Once the data is gathered, it is stored in a single location. This store is interchangeably referred to as “data warehouse or data mart.” There is, however, a slight difference between the scope of the two. While a data warehouse accumulates data from any part of the organization, data mart only incorporates data from a particular area or department of the organization.

The Store function saves the data in formats that allow for fast retrieval and analysis. It also aggregates numerous individual data transactions for determining particular outputs. The Store functions help in optimizing the data for online analytical processing (OLAP).

16. Describe the Model Function in Power BI

The Model function increments the role of the Store function. It mainly serves two purposes. It presents the queried data to the users in a visual and comprehensible form without any tables or field names.

Secondly, it securely stores internal formulas to perform business calculations in a single location. This eliminates the need to re-create the calculations every time a need arises. They can simply be pulled out using the model function. 

17. What is the use of Visualise function in Power BI?

The Visualize function is responsible for data analysis and data visualization. It helps in creating charts, tables as well as gauges on reports and dashboards. While some visualizations serve specific purposes, others are created for broad-based sharing across Power BI networks. 

Read: Top 10 Data Visualization Types

18. Describe the role of the Share function in Power BI

The share function develops a convenient mechanism for sharing and delivery of the content produced in Power BI among the organization or chosen users. It creates a common location where users can access the content. Needless to say, this location is fortified with proper security measures to enable only authorized access.

19. What are DAX functions in Power BI?

DAX is also known as Data Analysis Expressions. DAX functions are one of the three fundamental concepts of DAX. The other two concepts are syntax and context.

DAX functions are formulas that PowerBI uses to carry out calculations using unique values. These values are otherwise called arguments and they work similarly in Microsoft Excel. With DAX, users are able to work on relational data, and even large datasets, to perform mathematical operations, customize conditional logic, collect data from related tables, perform advanced calculations, among other functions.

Learn more on DAX functions here.

20. What is the Direct Query Method in Power BI and what are its advantages?

The direct query method is one of the several methods used to prepare data for tasks by collecting and transforming data from different sources before loading into a model. Some of the other query methods in the Power Query Editor tool include Import, DAX Query, M Language, Web Connector, Folder Connector, SQL Server Database Connector, amongst others.

The direct query method has a number of major advantages over the other query methods. These advantages include:

• It allows users to access and use real-time data from the database, without needing to import the data into a Power BI file.
• There is no limit of file size that can be used in this method, as it allows direct use from the source rather than importing.
• It allows the user to adapt the security features of the source database, including any access control or restrictions.
• Direct query encourages consistency in values as any change made in the data source automatically applies to the entire Power BI report.

Conclusion

Power BI has emerged as a vital tool to transform the quality of business content and streamline the process of sharing such content. In today’s world, where digitization and innovation go hand in hand to give your career the much-needed oomph, a thorough knowledge of Power BI can not only improve your efficiency but also make you an indispensable asset to your organization.

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