Power BI Interview Questions

Power BI provides different refresh options, such as Scheduled Refresh, which automatically updates data at specified intervals, and On-Demand Refresh, allowing users to manually trigger data refresh. There's also the option for Refresh Now, which updates the data immediately.

Power BI supports various connectivity modes, including Import mode where data is loaded into Power BI, DirectQuery mode allowing live connections to data sources, and Live Connection mode for connecting to datasets stored in the Power BI service.

Power BI Desktop is a free application that serves as the authoring tool for creating Power BI reports and dashboards. It allows users to connect to different data sources, transform and model data, and design visually appealing reports before publishing them to the Power BI Service.

In Power BI, data can be stored in the Power BI Service, a cloud-based platform provided by Microsoft. Users can upload and refresh datasets in the Power BI Service, making the data accessible to other users within the organisation.

Power BI offers different views, including a Reading view for consuming reports, an Editing view for modifying reports in Power BI Desktop, and a dashboard view for organising and interacting with multiple reports and visualisations in a consolidated manner.

Power BI supports various formats for importing and exporting data, including Excel workbooks, CSV files, SQL Server databases, and cloud-based sources like Azure SQL Database and SharePoint Online.

Power BI can connect to a wide range of data sources, including Excel workbooks, SQL Server databases, Azure services, SharePoint lists, online services like Google Analytics, and many other data repositories, ensuring flexibility and versatility in data integration.

The building blocks of Power BI include:

• Power Query: Used for data transformation and cleaning.
• Power Pivot: Enables data modelling and creating relationships between data tables.
• Power View: enables interactive exploration and visualisation of data.
• Power Map: Allows for the creation of 3D geographical visualisations.
• Power Q&A: Enables natural language querying of data.
• Power BI Desktop: The authoring tool for creating Power BI reports and dashboards.
• Power BI Service: The cloud-based platform for publishing, sharing, and collaborating on Power BI content.

Power BI comes in three main versions:

• Power BI Desktop: The free authoring tool for creating reports and dashboards.
• Power BI Pro: A subscription-based service that allows sharing and collaboration on reports.
• Power BI Premium: A more advanced subscription that provides dedicated cloud resources, better performance, and additional features.

DAX functions in Power BI are significant for:

• Custom Calculations: Users can create tailored calculations to meet specific analytical requirements.
• Aggregations: DAX allows for the creation of complex aggregations and summaries of data.
• Data Modeling: It plays a crucial role in defining relationships and hierarchies in data models.

Power BI services refer to the cloud-based platform provided by Microsoft for sharing, collaborating, and distributing Power BI reports and dashboards. It enables users to publish and access reports online, schedule data refreshes, and interact with dashboards.

Power BI operates by connecting to various data sources, transforming and modelling the data using Power Query and Power Pivot, creating visualisations in Power BI Desktop, and then sharing and collaborating on the reports and dashboards through Power BI services.

Custom visuals in Power BI are user-developed or community-contributed visualisations that extend the capabilities of standard visualisations. These can be imported and used in Power BI reports to provide unique and specialised ways to present data.

Power BI caters to a diverse user base, including business analysts, data scientists, executives, IT professionals, and developers. Each category of users may have different roles, responsibilities, and levels of expertise in creating, analysing, or managing Power BI reports and dashboards.