Class representing a MongoDB aggregation pipeline. More...

#include <pipeline.hpp>

Public Member Functions
	pipeline ()
	Creates a new aggregation pipeline.

	pipeline (pipeline &&) noexcept
	Move constructs a pipeline.

pipeline &	operator= (pipeline &&) noexcept
	Move assigns a pipeline.

	~pipeline ()
	Destroys a pipeline.

pipeline &	group (bsoncxx::document::view_or_value group)
	Groups documents by some specified expression and outputs to the next stage a document for each distinct grouping.

pipeline &	limit (std::int32_t limit)
	Limits the number of documents passed to the next stage in the pipeline.

pipeline &	lookup (bsoncxx::document::view_or_value lookup)
	Performs a left outer join to an unsharded collection in the same database to filter in documents from the "joined" collection for processing.

pipeline &	match (bsoncxx::document::view_or_value filter)
	Filters the documents.

pipeline &	out (std::string collection_name)
	Takes documents returned by the aggregation pipeline and writes them to a specified collection.

pipeline &	project (bsoncxx::document::view_or_value projection)
	Projects a subset of the fields in the documents to the next stage of the pipeline.

pipeline &	redact (bsoncxx::document::view_or_value restrictions)
	Restricts the contents of the documents based on information stored in the documents themselves.

pipeline &	sample (std::int32_t size)
	Randomly selects the specified number of documents that pass into the stage and passes the remaining documents to the next stage in the pipeline.

pipeline &	skip (std::int32_t skip)
	Skips over the specified number of documents that pass into the stage and passes the remaining documents to the next stage in the pipeline.

pipeline &	sort (bsoncxx::document::view_or_value ordering)
	Sorts all input documents and returns them to the pipeline in sorted order.

pipeline &	unwind (std::string field_name)
	Deconstructs an array field from the input documents to output a document for each element.

bsoncxx::document::view	view () const

Detailed Description

Class representing a MongoDB aggregation pipeline.

Constructor & Destructor Documentation

◆ pipeline()

mongocxx::pipeline::pipeline ( )

Creates a new aggregation pipeline.

See also: http://docs.mongodb.org/manual/core/aggregation-pipeline/

Member Function Documentation

◆ group()

pipeline & mongocxx::pipeline::group ( bsoncxx::document::view_or_value group )

Groups documents by some specified expression and outputs to the next stage a document for each distinct grouping.

The output documents contain an _id field which contains the the distinct key for that group. The output documents can also contain computed fields that hold the values of some accumulator expression grouped by the group's _id field.

Note: group does not order output documents.

See also: http://docs.mongodb.org/manual/reference/operator/aggregation/group/#pipe._S_group

Parameters

group the group expression, as a document.

◆ limit()

pipeline & mongocxx::pipeline::limit ( std::int32_t limit )

Limits the number of documents passed to the next stage in the pipeline.

See also: http://docs.mongodb.org/manual/reference/operator/aggregation/limit/#pipe._S_limit

Parameters

limit the number of documents to which output should be limited.

◆ lookup()

pipeline & mongocxx::pipeline::lookup ( bsoncxx::document::view_or_value lookup )

Performs a left outer join to an unsharded collection in the same database to filter in documents from the "joined" collection for processing.

See also: https://docs.mongodb.org/manual/reference/operator/aggregation/lookup/

Parameters

lookup the lookup expression, as a document with the following fields: from: <collection to join> localField: <field from the input documents> foreignField: <field from the documents of the "from" collection> as: <output array field>

◆ match()

pipeline & mongocxx::pipeline::match ( bsoncxx::document::view_or_value filter )

Filters the documents.

Only the documents that match the condition(s) specified by the filter will continue to the next pipeline stage.

See also: http://docs.mongodb.org/manual/reference/operator/aggregation/match/#pipe._S_match

Parameters

filter the filter.

◆ out()

pipeline & mongocxx::pipeline::out ( std::string collection_name )

Takes documents returned by the aggregation pipeline and writes them to a specified collection.

This stage must be the last stage in the pipeline. The out operator lets the aggregation framework return result sets of any size.

See also: http://docs.mongodb.org/manual/reference/operator/aggregation/out/#pipe._S_out

Parameters

collection_name the name of the collection where the output documents should go

◆ project()

pipeline & mongocxx::pipeline::project ( bsoncxx::document::view_or_value projection )

Projects a subset of the fields in the documents to the next stage of the pipeline.

See also: http://docs.mongodb.org/manual/reference/operator/aggregation/project/#pipe._S_project

Parameters

projection projection specification.

◆ redact()

pipeline & mongocxx::pipeline::redact ( bsoncxx::document::view_or_value restrictions )

Restricts the contents of the documents based on information stored in the documents themselves.

See also: http://docs.mongodb.org/manual/reference/operator/aggregation/redact/#pipe._S_redact

Parameters

restrictions the document restrictions.

◆ sample()

pipeline & mongocxx::pipeline::sample ( std::int32_t size )

Randomly selects the specified number of documents that pass into the stage and passes the remaining documents to the next stage in the pipeline.

See also: http://docs.mongodb.org/manual/reference/operator/aggregation/sample/#pipe._S_sample

Parameters

size	the number of input documents to select.

◆ skip()

pipeline & mongocxx::pipeline::skip ( std::int32_t skip )

Skips over the specified number of documents that pass into the stage and passes the remaining documents to the next stage in the pipeline.

See also: http://docs.mongodb.org/manual/reference/operator/aggregation/skip/#pipe._S_skip

Parameters

skip	the number of input documents to skip.

◆ sort()

pipeline & mongocxx::pipeline::sort ( bsoncxx::document::view_or_value ordering )

Sorts all input documents and returns them to the pipeline in sorted order.

See also: http://docs.mongodb.org/manual/reference/operator/aggregation/sort/#pipe._S_sort

Parameters

ordering document specifying the ordering by which the documents are sorted.

◆ unwind()

pipeline & mongocxx::pipeline::unwind ( std::string field_name )

Deconstructs an array field from the input documents to output a document for each element.

Each output document is an input document with the value of its array field replaced by an element from the unwound array.

See also: http://docs.mongodb.org/manual/reference/operator/aggregation/unwind/#pipe._S_unwind

Parameters

field_name the name of the field to unwind.

◆ view()

bsoncxx::document::view mongocxx::pipeline::view ( ) const

Returns: A view of the underlying BSON document this pipeline represents.

The documentation for this class was generated from the following file:

src/mongocxx/pipeline.hpp

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ pipeline()

Member Function Documentation

◆ group()

◆ limit()

◆ lookup()

◆ match()

◆ out()

◆ project()

◆ redact()

◆ sample()

◆ skip()

◆ sort()

◆ unwind()

◆ view()