docs: document DAX cross-view filtering

docs-mintlify/docs.json

@@ -515,6 +515,7 @@
                 "group": "DAX API",
                 "root": "reference/core-data-apis/dax-api/index",
                 "pages": [
+                  "reference/core-data-apis/dax-api/cross-view-filter",
                   "reference/core-data-apis/dax-api/reference"
                 ]
               }

docs-mintlify/reference/core-data-apis/dax-api/cross-view-filter.mdx

@@ -0,0 +1,88 @@
+---
+title: Cross-view filtering
+description: "Enable cross-view filtering in the DAX API to build dashboards that span multiple views in Power BI."
+---
+
+By default, the [DAX API][ref-dax-api] exposes each [view][ref-views] as a
+separate perspective in [Power BI][ref-powerbi]. Visualizations from different
+views can't share the same filters, and a single report can't combine measures
+and dimensions across views.
+
+Cross-view filtering removes this limitation, letting you build dashboards
+that span multiple views and apply filters consistently across visualizations.
+It is supported in both [Live connection](#live-connection-mode) and
+[DirectQuery](#directquery-mode) modes.
+
+To use cross-view filters such as slicers, you must enable single-perspective mode
+in the DAX API. To enable single-perspective mode in the DAX API,
+set the `CUBEJS_DAX_SINGLE_PERSPECTIVE` environment variable to `true`.
+
+In single-perspective mode, all views are exposed as part of a single perspective.
+This allows you to use a single connection and show visualizations from different
+views on the same dashboard.
+
+<Warning>
+
+Single-perspective mode changes the way views are exposed by the DAX API.
+Because of that, it is not backwards-compatible with dashboards created before
+enabling this environment variable.
+
+</Warning>
+
+## Live connection mode
+
+In Live connection mode, cross-view filters work automatically, provided that
+the following two conditions are met:
+
+- The column used in the filter must be present in every view that the
+cross-filter has to be applied to, and named exactly the same in each view.
+- The column in all such views must resolve to the same cube member.
+
+For example, if views `orders_view` and `users_view` both expose a column named
+`address_country` pointing to the `country.country` cube member, cross-filtering
+will be applied across these views.
+
+If the `address_country` column in `orders_view` points to `orders.country`
+while the `address_country` column in `users_view` points to `users.country`,
+cross-filtering will not be applied, because the columns resolve to different
+cube members.
+
+Likewise, if `orders_view` exposes an `address_country` column pointing to
+`country.country` and `users_view` exposes a `country` column also pointing to
+`country.country`, cross-filtering will not be applied, because the column
+names differ between the views.
+
+## DirectQuery mode
+
+In DirectQuery mode, cross-view filters require the same two conditions as in
+[Live connection mode](#live-connection-mode): the filter column must be
+present in every view with the exact same name, and it must resolve to the
+same cube member across those views.
+
+In addition, you must manually configure relationships between tables in Power
+BI so that filters propagate across views:
+
+- Open **Model view** in the left sidebar.
+- On the right, open the **Data** sidebar, then the **Model** tab.
+- Right-click **Relationships** and choose **New relationship**.
+- In the **Properties** sidebar, select a table and a column.
+- For cardinality, choose **Many to many (\*:\*)**. Ignore the warning.
+- Select another table with the same column.
+- For cross-filter direction, select **Both**.
+- Click **Apply changes**.
+
+Once the relationship is configured correctly, cross-view filters will work in
+DirectQuery mode.
+
+The steps above describe configuring a relationship between two tables. When
+many views need to be cross-filtered, the best practice is to create a single
+view in the Cube data model that includes all the columns from the views that
+need to be cross-filtered, and then create relationships between this large
+view and each of the other views. This keeps the relationship graph in Power
+BI simple and avoids configuring pairwise relationships between every
+combination of views.
+
+
+[ref-dax-api]: /reference/core-data-apis/dax-api
+[ref-views]: /docs/data-modeling/views
+[ref-powerbi]: /admin/connect-to-data/visualization-tools/powerbi

docs-mintlify/reference/core-data-apis/dax-api/index.mdx

@@ -73,8 +73,20 @@ The DAX API only exposes [views][ref-views], not cubes.
 
 </Info>
 
+## Cross-view filtering
+
+By default, each view is exposed as a separate perspective in Power BI, so
+visualizations from different views can't share the same filters. Cross-view
+filtering lets you build dashboards that span multiple views and apply filters
+consistently across visualizations, in both Live connection and DirectQuery
+modes.
+
+See [Cross-view filtering][ref-cross-view-filter] for details on how to enable
+and use it.
+
 
 [ref-powerbi]: /admin/connect-to-data/visualization-tools/powerbi
+[ref-cross-view-filter]: /reference/core-data-apis/dax-api/cross-view-filter
 [link-dax]: https://learn.microsoft.com/en-us/dax/
 [ref-sql-api]: /reference/sql-api
 [ref-ref-dax-api]: /reference/dax-api/reference