Using Kettle 8.1, I'm piloting a MongoDB migration of collections via MongoDB Input/Output steps as below:
Since the keys of the documents are variable, I checked the "Output single JSON field" as below:
The MongoDB Output step simply reads the "json" output field from the source step.
Then, the migrated collection added a wrapper key, _id, for each document as below:
What's the best way to migrate the source collection to the target as it is?