BI Wizard - Enable Dimension Writeback
Applies to: 
SQL Server Analysis Services 
Azure Analysis Services
Fabric/Power BI Premium
Add the dimension writeback enhancement to a cube or dimension to allow users to manually modify the dimension structure and members. Updates to a write-enabled dimension are recorded directly in the dimension table. This enhancement changes the WriteEnabled property setting for a dimension.
To add dimension writeback, you use the Business Intelligence Wizard, and select the Enable dimension writeback option on the Choose Enhancement page. This wizard then guides you through the steps of selecting a dimension to which you want to apply dimension writeback and setting this option for the selected dimension.
Note
Writeback is supported for SQL Server relational databases and data marts only.
Selecting a Dimension
On the first Enable Dimension Writeback page of the wizard, you specify the dimension to which you want to apply dimension writeback. The dimension writeback enhancement added to this selected dimension will result in changes to the dimension. These changes will be inherited by all cubes that include the selected dimension.
Setting Dimension Writeback Capability
On the second Enable Dimension Writeback page of the wizard, you actually set the Enable writeback in the dimension option. Selecting this option automatically sets the WriteEnabled property of the dimension to True. Clearing this option automatically sets the property to False.
Remarks
When you create a new member, you must include every attribute in a dimension. You cannot insert a member without specifying a value for the key attribute of the dimension. Therefore, creating members is subject to any constraints (such as non-null key values) that are defined on the dimension table. You should also consider columns optionally specified by dimension properties, such as columns specified in the CustomRollupColumn, CustomRollupPropertiesColumn or the UnaryOperatorColumn dimension properties.
Warning
If you use SQL Azure as a data source to perform writeback into an Analysis Services database, the operation fails. This is by design, because the provider option that enables multiple active result sets (MARS) is not turned on by default.
The workaround is to add the following setting in the connection string, to support MARS and to enable writeback:
"MultipleActiveResultSets=True"
For more information see Using Multiple Active Result Sets (MARS).