HasUnionWith¶

interface HasUnionWith<Document : Any> : Pipeline<Document>

Pipeline implementing the $unionWith stage.

Inheritors¶

AggregationPipeline

Properties¶

`context`¶

@LowLevelApi



abstract val context: BsonContext

The context used to generate this pipeline.

Functions¶

`reinterpret`¶

@DangerousMongoApi



@LowLevelApi



abstract fun <New : Any> reinterpret(): Pipeline<New>

Changes the type of the returned document, with no type-safety.

`toString`¶

abstract override fun toString(): String

JSON representation of this pipeline.

unionWith¶

open fun unionWith(other: HasUnionWithCompatibility<Document>): Pipeline<Document>

Combines two aggregations into a single result set.

$unionWith outputs the combined result set (including duplicates) to the next stage. The order in which the combined result set documents are output is unspecified.

Namespacing¶

other must be a pipeline from the same namespace. It may be a pipeline from the same collection or another collection, as long as they are both part of the same namespace.

Example¶

interface Vehicle {
    val brand: String,
}

class Car(
    override val brand: String,
    val enginePower: Int,
) : Vehicle

class Bike(
    override val brand: String,
    val hasBasket: Boolean
)

val selectedCars = cars.aggregate()
    .match { Car::enginePower gt 30 }
    .project { include(Car::brand) }
    .reinterpret<Vehicle>()

val selectedVehicles = bikes.aggregate()
    .project { include(Bike::brand) }
    .reinterpret<Vehicle>()
    .unionWith(selectedCars)
    .limit(5)
    .toList()

External resources¶

Official documentation

`withStage`¶

@DangerousMongoApi



@LowLevelApi



abstract fun withStage(stage: BsonNode): Pipeline<Document>

Creates a new pipeline that expands on the current one by adding stage.

`writeTo`¶

@LowLevelApi



abstract fun writeTo(writer: BsonValueWriter)

Writes the entire pipeline into writer.