Can we create complex transactional FIORI apps using RAP?

[coishr]

We have to migrate ESS' webdynpro applications to UI5 Fiori apps. But our webdynpro applications are very complex and bulky. We are receiving a lot of input data in non-tabular format and then processing through complex logic. There are numerous screen level validations as well. Upon processing, the data is written down in multiple standard as well as custom tables. 

Can we create such complex Fiori apps using SAP RAP Model or we should follow some other model for this task. One approach is to create multiple ODATA services without CDS view and Annotations and then process the data in individual function modules. CDS/BOPF/RAP are appropriate for tiny applications where not much front end coding is required.

For example, can we create travel expense application using SAP RAP model ?

[thomas_mller13]

There is a concept called "Draft Handling" for UI5 that is intended to substitute stateful transaction handling. Of course this is a crutch, but it should actually solve your problem.

[coishr]

my query is i dont want to create list report based apps. i will have around 50+ individual input fields. some inputs will be in tabular format. and all these inputs will be processed after applying client side validations and then the results will be updated in backend ERP table. Whats the best way out to achieve this ? Would RAP be able to fulfill this requirement ?