Hi Laksham,
How about writing an additional piece of code to identify if request is for create or update in Create Deep Entity itself.
As when creating you will not be having key value, and when updating you should be having key value for which you are updaing.
Lets say after reading Payload in structure.
io_data_provider->read_entry_data( IMPORTING es_data = ls_struct ).
if ls_struct-key is initial. "Create
<Your Create Logic>
elseif ls_struct-key is not initial. "Update
<Your Update Logic>
endif.
Regards,
Tarun