How does the Find Changes shape work? I'm assuming it compares two documents and finds the changes. So I understand that one of the documents is the one being made in the process, but what is the second one?
Below two articles will help you understand the use of Find Changes shape. To answer your question in brief, the first set of documents that are processed will be a reference for comparing subsequent documents and perform add/update operation accordingly.
Find Changesshape example
Find Changes Shape will check whether the document is update or added or deleted form the receiving source data where the document you are receiving.
It will Compare the record weather you added the fields in record or deleted the fields or update the fields it will compare.If you are going to add new record it will go into the add field , if you are updating the existing record it will go into the update field , if you are deleting the record it will go in to the delete field.
Retrieving data ...