Method: Mongo::Collection#aggregate

Defined in:
lib/mongo/collection.rb

#aggregate(pipeline, options = {}) ⇒ View::Aggregation

Perform an aggregation on the collection.

Examples:

Perform an aggregation.

collection.aggregate([ { "$group" => { "_id" => "$city", "tpop" => { "$sum" => "$pop" }}} ])

Parameters:

  • pipeline (Array<Hash>) —

    The aggregation pipeline.

  • options (Hash) (defaults to: {}) —

    The aggregation options.

Options Hash (options):

  • :allow_disk_use (true | false) —

    Set to true if disk usage is allowed during the aggregation.

  • :batch_size (Integer) —

    The number of documents to return per batch.

  • :bypass_document_validation (true | false) —

    Whether or not to skip document level validation.

  • :collation (Hash) —

    The collation to use.

  • :comment (Object) —

    A user-provided comment to attach to this command.

  • :hint (String) —

    The index to use for the aggregation.

  • :let (Hash) —

    Mapping of variables to use in the pipeline. See the server documentation for details.

  • :max_time_ms (Integer) —

    The maximum amount of time to allow the query to run, in milliseconds. This option is deprecated, use :timeout_ms instead.

  • :session (Session) —

    The session to use.

  • :timeout_ms (Integer) —

    The operation timeout in milliseconds. Must be a non-negative integer. An explicit value of 0 means infinite. The default value is unset which means the value is inherited from the collection or the database or the client.

Returns:

Since:

  • 2.1.0



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# File 'lib/mongo/collection.rb', line 575

def aggregate(pipeline, options = {})
  View.new(self, {}, options).aggregate(pipeline, options)
end