面试题与答案

Power BI is a business analytics service by Microsoft that provides interactive visualizations and business intelligence capabilities with an interface simple enough for end users to create their own reports and dashboards.

A data model in Power BI is a collection of data tables, relationships, and calculations that are used to create meaningful visualizations and insights.

A slicer in Power BI is a visual control that allows users to filter data in a report. It provides a way to easily select and view specific data points or ranges.

Power BI reports can be shared by publishing them to the Power BI Service, where users can access and view the reports online. Sharing options include sharing a dashboard, creating a shareable link, or embedding the report in a website.

To create a hierarchy in Power BI, you can drag and drop related fields onto each other in the Fields pane. For example, you can create a date hierarchy by dragging the Year, Quarter, and Month fields onto the axis in a visual.

The 'Card' visual in Power BI is used to display a single, key data point. It is often used to show a summary or a key performance indicator (KPI) in a concise and easily readable format.

The 'Card' visual in Power BI is used to display a single, key data point. It is often used to show a summary or a key performance indicator (KPI) in a concise and easily readable format.

Power BI Desktop is a standalone application for creating Power BI reports, while Power BI Service is a cloud-based service for publishing, sharing, and collaborating on Power BI reports and dashboards.

Calculated columns in Power BI are created using Data Analysis Expressions (DAX) in Power BI Desktop. You can use DAX functions to define calculations based on existing columns in your data model.

Measures in Power BI are calculations applied to data in a report. Unlike calculated columns, measures are dynamic and can change based on user interactions. They are created using Data Analysis Expressions (DAX).

Power BI Gateway is used to connect Power BI reports and dashboards to on-premises data sources. It acts as a bridge between Power BI Service in the cloud and the data stored locally.

Power BI Report Server is an on-premises version of Power BI Service. While Power BI Service is a cloud-based solution, Power BI Report Server allows organizations to host and manage reports on their own servers.

Row-level security in Power BI allows you to restrict data access based on user roles. It is implemented using DAX filters to control which data users can see based on their role assignments.

A calculated table in Power BI is created using DAX expressions. You can define calculations based on existing tables or columns in the data model. The new table is then used in the report.

Power BI Dataflows allow users to extract, transform, and load (ETL) data into a Power BI dataset. It provides a way to centrally manage and reuse data preparation steps across multiple reports and dashboards.

Time intelligence in Power BI involves using DAX functions to analyze and compare data over time. Functions like TOTALYTD, SAMEPERIODLASTYEAR, and DATESBETWEEN are commonly used for time-based calculations.

The 'Drillthrough' feature in Power BI allows users to navigate from a summary report to a detailed report by clicking on a data point. It provides a way to explore data at a more granular level.

Calculated columns in Power Query are created using the 'Add Column' tab in Power Query Editor. You can use M language expressions to define calculations based on existing columns in the data.

Power Query is used for data transformation and shaping in Power BI. It allows you to connect to various data sources, clean and transform the data, and then load it into the Power BI data model.

A Power BI gateway cluster is a group of multiple gateway installations that work together to provide high availability and load balancing. It ensures continuous connectivity to on-premises data sources.

The 'M' language is used in Power BI's Power Query Editor for data transformation and manipulation. It is a functional language that helps define the steps to clean and shape data before loading it into the data model.

The Power BI REST API allows developers to embed Power BI reports and dashboards into custom applications. It provides programmatic access to Power BI artifacts, enabling automation and integration with other services.

In Power Query, errors can be handled using the 'try...otherwise' construct. This allows you to specify alternate values or actions when an error occurs during data transformation.

Custom visuals in Power BI can be created using the Power BI Developer Tools in Visual Studio Code. Developers can use TypeScript and the Power BI JavaScript API to build and deploy custom visuals.