Mapping is one of the functionalities in Dataverse Model Driven Apps that can still only be configured using the Classic Editor.
Mapping allows you to create a new record and use already available information from the origin record in the new record without the need of writing any code. But there are some limitations:
- Mapping data will only be synchronized during the creation of the new record. Future updates will not be synchronized
- Only data from one record can be synchronized to the new record
- Field types and metadata must be a 100% match between source and target
- Choice should be of type global
- Mapping is only available fro 1:N
When you are already in Power Platform Maker Portal you can easily navigate to the Classic Editor by navigating to the table, where you want to add or edit the mapping and click on the 3 dots to select Switch to Classic
Inside the Classic Editor, Navigate to the N:1 Relationships and select the Relationship, where you want to edit the mapping or create a new one. By double-click on the relationship a pop-up window opens, where you can Navigate to the Mappings (if available). If mappings are already available for this relationship, all existing mappings are shown in the view, showing source and target and at the bottom of the view you can see the number of already existing mappings.
By clicking on New, another pop-up window opens where you can select the columns that you want to map between the two entities the relationship is for. Please have in mind, that the fields must be created first in both entities and metatdata of the fields must match.
In the Create Field Mapping window, select the matching source and target entity fields and click OK. The newly created mapping will be added to the previous list.
Note: If one field is available in the source list, but you cannot find it in the target list, and you are sure that the field is on both entities, then you should have a look at the already existing mappings. Each target field can only be used once during a mapping, while a source field can be used as source for multiple mappings.
After you have created all your mappings, click on Save and Close for the Mapping pop-up window, then click on save in the classic editor for the changes done on the entity and as last step do not forget to publish the changes in the classic editor.