Extended Table
When the Use Extended Table is toggled on (see Visual Settings), the function adds read-only columns that are not part of the chosen Storage table. These columns are fetched from a Semantic model and are shown in the grid. When a Semantic model is attached, number of rows that will be showed in the grid will be a merged result from the Storage table and the Semantic model.
To fetch data from a Semantic model, the user must have access to the workspace.
If the user is a workspace viewer, it need Build permissions in the semantic model that you are referencing for RLS (Row Level Security) to work. See https://learn.microsoft.com/en-us/power-bi/connect-data/service-datasets-manage-access-permissions
When Use Extended Table is toggled on, you will see three dropdowns which let you set from which table the data should be coming from.
The first time you toggle on the Semantic model, you must grant Aimplan permission to access your semantic model.
To use an Extended table, you must select a Workspace, Semantic Model, and a table within the model.
The users who will use the report must have access to the selected workspace. If a user doesn't have access to the workspace an error will occur.
Once a table is selected, all columns within that table will be displayed in field list on the left.
The list of tables is filtered based on the primary key columns defined in the Storage table. The table must contain all the primary key columns to be shown in the list.
When you preview the report (see below), you will see the chosen columns in the Data Input Table. When editing, the columns from the Semantic model are disabled.
The columns from the Semantic model cannot be set to editable but you can format the columns in the same way as the columns from the Storage table, i.e. set background or foreground color etc.
You can add rows if you have this enabled but the columns from the Semantic model will be blank as long the Primary key value(s) are missing in the Semantic model.
When you are done with the settings, you click on "Back to report" in the upper left corner to switch back to the report.