Creating Linked Dimensions

You can create links between dimensions in multiple models.

Prerequisites

If you are using live data models for blending, additional prerequisites and setup may be required. For more information, see Blending Data.

Context

You can use linked dimensions to create blended charts or tables that display data from multiple models.

Linked dimensions also let you create filters that simultaneously update all charts that include linked data. Filters on linked dimensions can be used at the story, page, and linked analysis level.

Note
  • The attributes of a dimension must match the attributes of the dimension it is linked to:

    • Description to Description
    • ID to ID

    If the attributes don't match, information might not be returned when a filter is created, and a “(No Value)” flag will appear for an unmatched dimension member.

  • Chart filters don't affect linked dimensions, because they're applied to a single chart.
  • Some dimension links may not apply filters to all charts. This happens when filters applied to one model can't be translated to meaningful filters on a second model.
  • For BW remote models, consider that the Description might be language-dependent.
  • Sorting doesn't work with linked dimensions.
Restriction
The Show Totals feature is not supported with linked dimensions.

Procedure

  1. Open the Link Dimensions dialog. There are two ways to access the dialog:
    • Select (Link Dimensions) from the menu bar.
      Note
      If there are already linked dimensions in the story, they will be listed. To use the existing link, select ( Edit Link). To create a new link, select Add Model Link.
      1. Select a chart or table.
      2. In the Builder tab, in the Data Source area, select Add Linked Models and then select Create Model Link.
    The Link Dimensions dialog appears.
  2. Select a model from the list of models included in your story, or in the drop-list select Add Model to search through the models you have access to.

    To change how the dimensions are displayed in the Select a model area, select Start of the navigation path Next navigation step Data SamplesEnd of the navigation path and then select an attribute:

    • Description
    • ID
    • ID and Description
    Note

    By default, only descriptions are retrieved. For dimensions that don't have a Description attribute, No Values will be displayed. Selecting ID or ID and Description gives a better indication of the true values available.

    Note

    For dimensions that have blank or empty strings for Description (""), the value of the ID attribute will be displayed. This can sometimes lead to an incorrect perception that two dimensions can be matched on their Description attribute when in fact the ID attribute should be used.

  3. Choose one or more dimensions.
    Note
    When you hover over a dimension, you can preview the dimension values.
  4. Choose a second model and select one or more dimensions.
    Note
    The attribute of a dimension must match the attribute of the dimension it is linked to. If it doesn't match, when a filter is created, information may not be returned.
  5. (Optional) In the Matched Dimensions area, select a dimension, select (Link Attribute) and then choose from the linking options.
    Option Description

    Link On: ID or Description.

    This feature is available on non-hierarchical dimensions and imported data source dimensions with level-based hierarchies.

    The setting will apply to both filtering across models and blending workflows. If no option is selected, then, by default, the following attributes are used:
    • For filtering across models, the ID attribute is used to propagate filters from source models to target models.

    • For blending, the Description attribute is used to match members between the linked dimensions.

    Selecting ID or Description is not possible for dimensions with parent-child hierarchies.

    Link On specific level-based hierarchy

    This option is available on dimensions with level-based hierarchies.

    • Links specifying level-based hierarchies can be used for filtering across models, but not for blending.

    • If a level-based hierarchy is selected, then the dimension can only be linked to another dimension with a level-based hierarchy that has the same number of levels. It is also assumed that the levels between the two level-based hierarchies match.

      For example, it is possible to link a two-level hierarchy representing Country-City to another two-level hierarchy representing Country-City or to a two-level hierarchy representing Continent-Country. However, only the first link would yield expected results.

    • For imported data sources, link on the dimension ID and the individual hierarchy properties, rather than the hierarchy itself.

    Link on matching hierarchies

    This option is not available for Live BW or Live Universe models.

    This setting is ON by default for any links created starting with version 2020.15 and OFF by default for any content created prior to 2020.15.

    • The setting applies to filtering across models and blending for import data models and Live HANA models.

    • Matching is done based on the hierarchy name/id and assumes that hierarchies with the same name have matching structure/members. For cases where this assumption is true, it is recommended to turn ON the option.

    • With the setting OFF:
      • Filtering across models will propagate filters on the default hierarchy: this can cause poor performance for source filters that use the non-default hierarchy.

      • Blending will use the default hierarchy in the secondary sub-query: this may not match members of the parent-child hierarchy set on the primary sub-query.

    • With the setting ON:
      • Filtering across models will propagate filters on the matching hierarchy (provided one exists) no matter which hierarchy is used in the source filter.

      • Blending will use the matching hierarchy (provided one exists) in the secondary sub-query based on the parent-child hierarchy set on the primary sub-query: this should result in better/more faithful blend results.

    • Setting can be activated via ellipsis (…) menu or the link status (/) icon and is synchronized to the same state for the two linked dimensions (i.e. it’s ON for both or OFF for both)

    Exclude descendants

    This option is available on dimensions with parent-child hierarchies and Live HANA model dimensions with level-based hierarchies.

    • The setting applies to filtering across models and it controls some performance-intensive aspects of the feature.

    • If the hierarchies have identical structure/members, ensure that the filtering is done using the currently selected members only. Be sure to select the Exclude descendants option.

    • If the hierarchies aren't identical, then you might need to filter on descendants to get the right filter result, at the cost of slower performance.

    By default, the Description attribute is used to match members between the linked dimensions. However, for non-hierarchical dimensions it is possible to change the attribute that is used for linking.

    Note
    Filtering across models on hierarchies can be performance intensive. There are a few things to consider:
    • If the hierarchies aren't identical, then you might need to filter on descendants to get the right filter result, at the cost of slower performance.

    • If the hierarchy is a level-based hierarchy for an import data model, we suggest that you link on ID and the individual hierarchy properties, rather than the hierarchy itself.

  6. Select Set.
  7. Review the links and if necessary, edit them or select Add Model Link to add more links.
  8. When finished, select Done.

Results

Linked dimensions appear in the dialog.