explode
Description
The explode
command transforms an array of N elements into N separate documents, each containing one element of the array at the specified keypath. It’s commonly used to “flatten” nested data structures for easier analysis or aggregation.
When using explode
, you can control whether to keep or remove the original document fields via the original
modifier:
original discard
removes all original fields, producing minimal output with just the exploded key.original preserve
retains the original document fields, duplicating them across the new documents.
Note
If the destination keypath already exists in the document, it is overwritten by the exploded value.
The default behavior is original discard
.
Syntax
Example
Use case: Represent each user permission as an individual document
Each log contains a list of permissions (scopes
) assigned to a user. To make permission-level analysis simpler, we can use explode
to create one document per permission, preserving the original fields for context.
Example data
Example query
Example output
{ "userid": "1", "scope": "read", "scopes": ["read", "write"] },
{ "userid": "1", "scope": "write", "scopes": ["read", "write"] },
{ "userid": "2", "scope": "read", "scopes": ["read", null] },
{ "userid": "2", "scope": null, "scopes": ["read", null] }
The explode
command expands each array element into its own document while keeping the original userid
and scopes
fields. This makes it easier to query and aggregate user permissions individually. id: explode