Recently I helped a CRM Fiori customer to implement several extension fields on CRM Opportunity application ( supports CRUD operations on those fields ).
Figure1: Extension field in WebUI
Figure2: Extension field in Fiori
In WebClient UI, there is no additional effort for developers to support extension field CRUD, if those fields are created by AET ( Application Extension Tool ), since most of the stuff are already handled by WebUI framework automatically. On the other hand, in Fiori, efforts must be spent both on frontend and backend.
If you are interested with how to achieve this in CRM Fiori, please refer to the series of blogs below.
This blog introduces how to extend the oData model for CRM Opportunity with extension field and expose the read operation on it via oData service. It contains pure backend development.
This blog introduces how to put the extension field on Opportunity UI detail view. It means after the steps of this blog is done, every time you navigate to the detail view of a given opportunity, you could see the value of extension field, that is, the read operation is supported. Both ui and backend development are needed.
This blogs introduces how to enable the extension field with update operation, which means you could change the value of extension field in UI and persist it to database repeatedly. Both ui and backend development are needed.
This blogs introduces how to enable the extension field with create operation, which means when you create a new opportunity, you could also specify the value of extension field in creation ui and it will be persisted to database together with other fields in opportunity header. Both ui and backend development are needed.