Introduction to BarChart v1.5

Power ON’s BarChart is a custom visual designed for Microsoft’s Power BI. It enhances the user experience by enabling end users to make permanent changes to data through write-back functionality. This means users can target measures and DAX expressions to modify data directly within their reports.

The BarChart product documentation provides a detailed overview of how to use this tool effectively. It covers common use-case implementations, proper configuration, and strategies for overcoming potential pitfalls. This documentation caters to both technical experts (such as developers, DBAs, and BI professionals) who have in-depth knowledge of SQL Server, SSAS Tabular models, Azure Services, and Power BI, as well as users who primarily concentrate on creating and preparing reports using Power BI Desktop.

BarChart enables users to modify figures that result from DAX expressions defined aggregations. In traditional dimensional modeling, these aggregations are calculated on fact tables, with the calculation context defined by dimensions that are in relation with the fact table. BarChart enables users to update the results of their measures.

Key features of BarChart include:

• Writing back values to the underlying data source.
• Modifying figures by using drag-and-drop interactions on data points.
• Changing the ratio of data points while maintaining total values.
• Creating comments on data points.

Following is the high-level overview of how write-back works for Tabular models. Depending on your data source (SSAS In-Memory, SSAS Direct Query, or SQL only) Power ON’s write-back service performs the following steps:

1. The service captures the modified value along with its tuple (the intersection of dimensions used in the calculation of measure for the given cell) and the user context. Based on the SSAS model structure (relationships, table queries, and measure definitions) the service composes T-SQL statements for execution.
2. It executes the compiled T-SQL statement against the underlying data source (fact table) to save the modifications.
3. For SSAS in-memory models, the service reprocesses the table. See Performance Optimization for more information.
4. It refreshes the visual to display the changes in the report.