Daily DAX : Day 176 INFO.ANNOTATIONS

 Okay, let's break down the INFO.ANNOTATIONS() DAX function in Power BI.

What is INFO.ANNOTATIONS()?

The INFO.ANNOTATIONS() function is a DAX informational function. Its purpose is to retrieve a table containing metadata about all the annotations defined within the current Power BI data model (or Analysis Services Tabular model).

Syntax

The syntax is very simple, as it takes no arguments:

Code snippet

INFO.ANNOTATIONS()

Return Value

This function returns a table with the following columns:

ObjectType (Text): Specifies the type of the model object that has the annotation (e.g., "TABLE", "COLUMN", "MEASURE", "HIERARCHY", "RELATIONSHIP", "MODEL").

ObjectName (Text): The name of the specific object (e.g., the table name like 'Sales', the column name like '[Revenue]', the measure name like '[Total Sales]'). For model-level annotations, this might be the database name or blank.

AnnotationName (Text): The name given to the specific annotation. This is defined by the person or tool that created the annotation.

AnnotationValue (Text): The value or content of the annotation.

How Annotations Get Into the Model

It's crucial to understand that you don't typically create annotations directly within the standard Power BI Desktop user interface. Annotations are usually added to the model's metadata using:

External Tools: Tools like Tabular Editor (versions 2 and 3) are commonly used to add, edit, and view annotations on various model objects.

Scripting: Using Tabular Model Scripting Language (TMSL) (often executed via SQL Server Management Studio - SSMS) or Analysis Management Objects (AMO) libraries in custom code allows programmatic addition of annotations.

Use Cases for INFO.ANNOTATIONS()

Since annotations allow you to store custom metadata directly within your model, the INFO.ANNOTATIONS() function becomes useful for accessing and leveraging this metadata within your reports or for analysis. Here are some key use cases:

Dynamic Report Documentation:

You could store descriptions, calculation logic explanations, or business definitions as annotations on measures, columns, or tables.

Use INFO.ANNOTATIONS() in a DAX query (e.g., in a Paginated Report data source, or potentially visualized in Power BI using specific techniques) to display this documentation dynamically, perhaps in tooltips or dedicated documentation pages within the report.

Report Configuration & Behavior:

Store configuration flags as annotations. For example, an annotation IsVisibleInReport=TRUE/FALSE on certain columns or measures.

Use INFO.ANNOTATIONS() within report logic (more common in external tools generating reports or complex DAX scenarios) to dynamically show/hide visuals or data based on these annotation flags.

Store formatting hints (though dedicated format strings are usually better for standard formatting).

Metadata Auditing and Analysis:

Analyze the annotations present in your model. You could create a report page showing all objects with a specific annotation type (e.g., all measures missing a 'Business Definition' annotation).

Track custom metadata like 'Data Owner', 'Source System', 'Validation Status', etc., that might be added via external processes or tools.

Custom Grouping or Categorization:

Assign custom categories or groups to measures or columns via annotations (e.g., MeasureGroup = 'Financial', MeasureGroup = 'Operational').

Use INFO.ANNOTATIONS() to retrieve these groupings and potentially use them for filtering or structuring report elements (though Display Folders are the more standard approach for simple grouping in the Fields list).

Example Scenario

Imagine you used Tabular Editor to add an annotation named "Description" to several of your key measures:

Measure [Total Sales] has Description = "Total net sales value across all regions."

Measure [Profit Margin] has Description = "Calculated as (Total Profit / Total Sales)."

You could then use a DAX query (perhaps in DAX Studio, SSMS, or as a source for another tool/report) to retrieve these descriptions:

Code snippet

EVALUATE

FILTER(

    INFO.ANNOTATIONS(),

    [AnnotationName] = "Description" && [ObjectType] = "MEASURE"

)

This query would return a table listing only the "Description" annotations specifically for objects of type "MEASURE", allowing you to see the measure names and their corresponding descriptions.

In summary, INFO.ANNOTATIONS() is a powerful function for developers and analysts who need to access custom metadata (annotations) stored within the Power BI model, often added via external tools, enabling dynamic documentation, configuration, and metadata analysis.