Merge the new result with the existing result if the output collection already exists.
Merge the new result with the existing result if the output collection already exists. If an existing document has the same key as the new result, overwrite that existing document.
Merge the new result with the existing result if the output collection already exists.
Merge the new result with the existing result if the output collection already exists. If an existing document has the same key as the new result, apply the reduce function to both the new and the existing documents and overwrite the existing document with the result.
Replace the contents of the collectionName
if the collection with the collectionName
exists.
The map reduce to collection actions.
These actions are only available when passing out a collection that already exists. This option is not available on secondary members of replica sets. The Enum values dictate what to do with the output collection if it already exists when the map reduce is run.
1.0