Summary
The following details offer a quick snapshot of this article’s core content and primary focus to ensure that it is most relevant to your needs.
- What: Cube dimension assignment
- When: Early build
- Why: Enable future flexibility
- How: Assign dimensions to specific Scenario Types and change “(Use Default)” to the Root dimension
Overview
To enable future flexibility, it is foundationally critical to properly configure the cube dimension assignments prior to loading data. Once data has been loaded to a cube, the assignments for the (Default) Scenario Type are locked in.
The Root dimension assignments in the above image can be updated on the (Default) Scenario Type in the future, but any Scenario Types that have data and are set to “(Use Default)” like the image below, cannot be changed.
This means that if not configured properly, the entire cube must abide by the updates to the (Default) Scenario Type.
If the cube dimensions are configured properly, additional dimensions can be added to specific Scenario Types in the future. The example use case illustrated in this guide is adding a customer dimension in Budget to expand the annual planning capabilities. This guide provides example configurations to illustrate the recommended approach and common misconfigurations.
Recommendation
When a cube is created, dimension assignments on specific Scenario Types are set to “(Use Default)” on the Cube Dimensions tab. To properly configure an application for extensibility and enable data model flexibility/expansion in the future, these settings should be updated for the active Scenario Types within each cube.
(Default) Scenario Type:
- Assign the Data Unit dimensions of entity and scenario.
- Leave all non-Data Unit dimensions as Root.
For all active Scenario Types:
- Entity and scenario will remain as “(Use Default).”
- All non-Data Unit dimensions should be assigned a specific dimension. Select Root for all unused dimensions. “(Use Default)” should not remain for any dimension.
- Leave inactive Scenario Types as-is until ready to be activated.
Use Case & Examples
Use Case:
A client with a live OneStream application wants to enable a customer dimension in Budget to expand their annual revenue planning capabilities and include their top customers. Data has already been loaded to Actual and a prior year Budget.
Configuration #1: Recommended Configuration
The recommended configuration of cube dimension assignments will enable the application to take full advantage of extensibility. This configuration will allow the addition of new dimensions to specific Scenario Types in the future and eliminate the need to “stub out” unused dimensions for future use.
To configure properly, the Data Unit dimensions (entity and scenario) will be assigned to the (Default) Scenario Type, and all remaining active dimensions will be assigned to their respective active Scenario Types. Any inactive dimensions should be set to "Root” instead of “(Use Default)”.
Recommended initial assignment is as follows:
|
(Default) |
Actual |
Budget |
 |
 |
 |
After the Actual and Budget Scenario Types both have data in them, we are still able to change our UD4 Dimension assignment in the Budget Scenario Type to include our new summary customer dimension.
**Be aware that once you hit save, the new UD4 assignment will be locked in, and you will be unable to change it if there is data in that cube and Scenario Type combination. Changing from a Root dimension is a one-time change that cannot be reverted if there is data in this cube and Scenario Type combination. **
After adding the new dimension to the Budget Scenario Type, one will see the history in UD4#None, and the new dimension members active for input in subsequent budget cycles. Since it was assigned to the specific Scenario Type and not (Default), you will notice that this new UD4 dimension is invalid for the Actual Scenario Type.
This configuration will also allow the future addition of UD5 and UD6 dimensions by following these same steps.
Configuration #2: Improper Assignment to the (Default) Scenario Type
A common error is to assign all dimensions to the (Default) Scenario Type and only use the Scenario Type-specific tabs for those that differ. This configuration will work and will also allow you to add additional dimensions in the future but is much less flexible. Additional dimensions in this setup must be assigned to the (Default) Scenario Type and will therefore apply to all active scenarios.
In the example below, all active dimensions have been assigned to the (Default) Scenario Type and a different Account dimension has been assigned to the Budget Scenario Type to enable the use of extensibility. The remaining non-Data Unit dimensions have been left as (Use Default) for both the Actual and Budget Scenario Types:
|
(Default) |
Actual |
Budget |
 |
 |
 |
In this setup, attempting to assign our new customer dimension to UD4 on the Budget Scenario Type:
Will display this error:
Due to the use of (Use Default) on the active Scenario Types, they are now locked into whatever the (Default) Scenario Type has set for these dimensions and they cannot be updated.
To add our new customer dimension, one is forced to assign it to the (Default) Scenario Type:
When assigning to the (Default) Scenario Type, you will notice that it works for Budget as required (same as the recommended configuration), but it is now active for the Actual Scenario Type as well which was not the desired result.
With this configuration, existing business rules and member formulas will need to be validated throughout the application to ensure the right intersections are specified. This additional dimension contains valid intersections in all Scenario Types; therefore, rules need to be more explicit in their filtering and writing of data. If written improperly or too open, this new dimension may cause a performance impact or zeros and other bad data being calculated in these new intersections.
Configuration #3: Improper Assignment of (Use Default)
Another erroneous configuration is to assign all dimensions to their respective Scenario Type but leave unused dimensions as (Use Default). This configuration will also work and will allow you to add additional dimensions in the future, but also is not as flexible as the recommended setup. Additional dimensions in this setup must be assigned to the (Default) Scenario Type and will therefore apply to all active scenarios.
In the example below, all active dimensions have been assigned to their respective Scenario Types. The remaining inactive dimensions have been left as (Use Default) for both the Actual and Budget Scenario Types:
|
(Default) |
Actual |
Budget |
|
|
 |
 |
In this setup, attempting to assign our new customer dimension to UD4 on the Budget Scenario Type will result in the same error as configuration #2 above:
Again, forcing the assignment to the (Default) Scenario Type which will apply to all active Scenario Types with the setting of (Use Default) for UD4.
This assignment will also work for Budget, but as with configuration #2 above, you will notice that it is now active for the Actual Scenario Type as well which was not the desired result.
As with configuration #2 above, existing business rules and member formulas should be validated throughout the application to ensure the right intersections are specified. Additional no input rules may be necessary to limit input to these intersections in Scenario Types that do not apply.
Considerations
The recommended configuration for cube dimension assignment eliminates the need to “stub out” unused dimensions for future use. If unused dimensions are assigned to “Root” on their respective Scenario Types, they can be changed in the future. One should not create a placeholder dimension for those that are unused (UD4, UD5, and UD6 in our example above) as this will only limit future flexibility.
If additional dimensions are not configured properly, you can only update from Root to a specific dimension once. If you accidentally save an incorrect dimension update, you’re locked into that change. Plan and make sure these settings are properly updated before saving the changes.
Despite adding flexibility for the future, configuring the cube dimensions in this way still does not allow you to change active dimensions with data.
Conclusion
As you can see from the examples above, non-Data Unit dimensions should be assigned to the cube by Scenario Type with (Use Default) changed to the Root dimension for those that are inactive at setup. Assigning non-Data Unit dimensions to the (Default) Scenario Type and leaving (Use Default) on the specific Scenario Types will limit the benefits and flexibility provided by extensibility. Improper setup will force the entire cube to conform to future updates to the (Default) Scenario Type. Conversely, assigning non-Data Unit cube dimensions to specific Scenario Types and utilizing the Root dimensions instead of (Use Default) will open additional growth opportunities for the application. This recommended configuration is also more flexible than “stubbing out” dimensions for future use as you do not have to consider the potential pitfalls related to that design.
