Power BI Interview Questions and Answers- Part 5

Answer:

In Power BI Desktop, you can define relationships between two tables in your data model using the following steps:

1. Open Power BI Desktop and create a new or open an existing report.
2. In the Fields pane on the right side of the screen, ensure that you have the tables you want to establish a relationship between.
3. Click on the “Manage Relationships” button in the Home tab of the ribbon. This will open the Manage Relationships dialog box.
4. In the Manage Relationships dialog box, click on the “New” button to create a new relationship.
5. Select the first table from the drop-down list under “Table” and choose the column that you want to relate to the other table from the drop-down list under “Column.”
6. Select the second table from the drop-down list under “Related Table” and choose the column that you want to relate to the first table from the drop-down list under “Related Column.”
7. Choose the Cardinality option that best describes the relationship between the two tables. The available options are “One-to-One,” “One-to-Many,” or “Many-to-Many.” Cardinality defines how rows in one table relate to rows in another table.
8. Specify the Cross filter direction by selecting one of the following options:
   • “Single” if you want the relationship to be applied in a single direction.
   • “Both” if you want the relationship to be bi-directional, allowing filtering in both directions.
9. Click on the OK button to create the relationship.
10. Repeat steps 4 to 9 if you have additional relationships to define.
11. After defining the relationships, click on the “Close” button to exit the Manage Relationships dialog box.

Answer:

In Import mode, data is loaded into Power BI’s in-memory engine called VertiPaq, providing fast and interactive visualizations. Changes to the data source do not affect the reports until a manual refresh is performed. In DirectQuery mode, Power BI connects directly to the data source in real-time, allowing reports to reflect the latest data. However, DirectQuery mode may have limitations on certain Power BI features and can be slower for complex queries.

Answer:

Yes, you can schedule data refresh for cloud-hosted Power BI reports. In the Power BI service, you can configure a refresh schedule for datasets. Depending on the type of data source, you may need to set up credentials and gateway connections to enable scheduled refresh.

Answer:

Power BI supports real-time data through DirectQuery mode or by using streaming datasets. With DirectQuery, you can connect to data sources that provide real-time data updates. Streaming datasets allow you to push data directly into Power BI using APIs, enabling real-time dashboards and visualizations.

Answer:

You can share Power BI reports in several ways:

1. Publish reports to the Power BI service and share them with specific individuals or groups within your organization.
2. Create a content pack or an app to package and distribute reports, dashboards, and datasets to other users or external customers.
3. Export reports to different formats like PDF or PowerPoint and share them via email or other communication channels.
4. Embed reports in external websites or applications using Power BI Embedded or the Power BI API.

Answer:

Power BI does not have a built-in feature to create custom functions. However, you can use Power Query Editor to create custom functions using M language. In Power Query Editor, you can define a function using the “let” statement and reuse it across multiple queries.

Answer:

Power BI Desktop is a Windows application used for creating and authoring Power BI reports and dashboards locally. It offers advanced data modeling capabilities and powerful visualization options. On the other hand, Power BI Service is a web-based platform where you can publish, share, and collaborate on Power BI content. It allows you to view and interact with reports and dashboards, schedule data refreshes, set up data gateways, and manage access permissions.

Answer:

To create a Key Performance Indicator (KPI) in Power BI, you can follow these steps:

• Open Power BI Desktop and connect to your data source.
• Once you have imported or connected to your data, navigate to the “Fields” pane on the right-hand side.
• Identify the measure or calculation you want to use as the basis for your KPI.
• Right-click on the measure and select “Quick Measures.”
• In the “Quick Measures” dialog box, select “KPI” from the list of calculation types.
• Provide a name for your KPI in the “Name” field.
• In the “Base value” section, select the measure or calculation that will represent the actual value for your KPI.
• In the “Target value” section, select the measure or calculation that will represent the target or goal for your KPI.
• Customize the formatting options to be displayed for different states of the KPI
• Click on the “OK” button to create the KPI.
• Power BI will create a new visual on the report canvas with your KPI. You can resize and format the visual as per your requirements.

Answer:

To generate a Power BI template, first design a report or dashboard in Power BI Desktop and save it as a template file. This template file can subsequently be employed by other users to craft new reports or dashboards with an identical structure and arrangement. To initiate the template creation process, navigate to the Home tab within Power BI Desktop, opt for Save As, and designate the file type as Power BI Template.

Answer:

Power BI enables the integration of Python and R programming scripts to enhance data analysis and visualization. In order to utilise R or Python with Power BI, one needs to install the required libraries and connect to a script from Power BI. Thereby, use Python or R script as a data source, create custom visuals, or transform data with code.

Answer:

Here are some ways a fact table can be used in data modeling:

1. Centralizing metrics: The fact table acts as a central repository for storing various metrics or measurements related to a specific business process.
2. Granularity and aggregation: The fact table captures the detailed, atomic-level data at the most granular level. However, it can also store aggregated data to support different levels of analysis. Aggregations are created by summarizing and grouping the data in the fact table based on different dimensions. It allows users to analyze data at different levels of detail and perform efficient queries.
3. Joining with dimension tables: Fact tables are typically associated with dimension tables through foreign key relationships. Dimension tables provide context or descriptive information about the metrics in the fact table. By joining the fact table with dimension tables, users can perform complex queries and slice the data based on various attributes.
4. Supporting analytics and reporting: The fact table forms the foundation for analytical queries and reporting in a data model. It enables users to analyze trends, patterns, and relationships between different dimensions and metrics. By querying and aggregating the data in the fact table, organizations can gain insights and make data-driven decisions.
5. Performance optimization: Fact tables are usually designed for optimized query performance. They are often indexed appropriately and pre-aggregated to improve query response times. By structuring the fact table efficiently, organizations can enhance the performance of analytical queries and reporting operations.

Answer:

Snowflake schema is a type of data warehouse schema used for organizing and structuring data in a relational database. It is an extension of the star schema, which consists of a central fact table connected to multiple dimension tables.

Answer:

Paginated reports in Power BI are a type of report format that is optimized for printing or generating high-quality, pixel-perfect outputs. Unlike other report types in Power BI, such as interactive or analytical reports, paginated reports are designed to fit well on printed pages or be exported to formats like PDF or Word.

Answer:

Here are a few key characteristics and features of paginated reports in Power BI:

• Structured layout
• Print optimizations
• Pixel-perfect rendering
• Advanced formatting options
• Data-driven reports

Answer:

A one-to-many relationship refers to a type of relationship between two tables in a data model. It represents a connection where one record in a table can be associated with multiple records in another table, but each record in the second table can be associated with only one record in the first table.

Answer:

Here are some differences between filters and slicers.

1. Functionality:
   • Filters are used to restrict or filter data based on specific criteria. When you apply a filter, it hides or removes data that doesn’t meet the specified conditions.
   • Slicers are interactive visual controls that allow users to filter or slice the data visually. They provide a user-friendly way to select values from a specific field or dimension. Slicers work hand-in-hand with filters, allowing users to easily select or deselect specific values to refine the displayed data.
2. User Interface:
   • Filters can be applied directly within a data analysis tool. They often provide a range of options to set conditions and are usually applied to specific columns or fields in a dataset.
   • Slicers are typically visual elements that are separate from the data analysis tool. They provide an intuitive interface for selecting values or options. Slicers can be placed on a dashboard or a separate sheet, and they visually represent the available options, making it easy for users to make selections.
3. Visual Feedback:
   • When a filter is applied, the data that doesn’t meet the specified conditions is either hidden or filtered out, resulting in a change in the displayed data. However, the filter itself may not be immediately visible or evident in the visual representation of the data.
   • Slicers provide visual feedback to indicate the selected values or options. They often highlight the selected values or provide some visual cue to show which options are currently active. This visual feedback helps users understand the applied filters and the impact on the displayed data.

Answer:

In Power BI, you can compare the target and actual values from a report using various visualization techniques. Here are a few common methods:

• Stacked Column Chart
• Line Chart
• Gauge Chart
• KPI Visual
• Column Chart

Answer:

No, it’s impossible to create multiple dynamic connections between two tables.

Answer:

TOP N isn’t accessible for the Page & Report Level Filters because their channels are related with different visuals.

Answer:

In Power BI, the COLLECT function is used to aggregate values from a column into a single value. It is primarily used in DAX formulas to perform calculations and create custom measures or calculated columns.