Struct Aggregate

pub struct Aggregate<'a, Session = ImplicitSession, T = Document> { /* private fields */ }

Run an aggregation operation. Construct with Database::aggregate or Collection::aggregate.

Implementations

impl<'a, Session, T> Aggregate<'a, Session, T>

pub fn with_type<U>(self) -> Aggregate<'a, Session, U>

Use the provided type for the returned cursor.

#[derive(Deserialize)]
struct PipelineOutput {
    len: usize,
}

let aggregate_cursor = database
    .aggregate(pipeline)
    .with_type::<PipelineOutput>()
    .await?;
let aggregate_results: Vec<PipelineOutput> = aggregate_cursor.try_collect().await?;

pub fn with_options(self, value: impl Into<Option<AggregateOptions>>) -> Self

Set all options. Note that this will replace all previous values set.

pub fn allow_disk_use(self, value: bool) -> Self

Enables writing to temporary files. When set to true, aggregation stages can write data to the _tmp subdirectory in the dbPath directory.

pub fn batch_size(self, value: u32) -> Self

The number of documents the server should return per cursor batch.

Note that this does not have any affect on the documents that are returned by a cursor, only the number of documents kept in memory at a given time (and by extension, the number of round trips needed to return the entire set of documents returned by the query).

pub fn bypass_document_validation(self, value: bool) -> Self

Opt out of document-level validation.

pub fn collation(self, value: Collation) -> Self

The collation to use for the operation.

See the documentation for more information on how to use this option.

pub fn comment(self, value: impl Into<Bson>) -> Self

Tags the query with an arbitrary Bson value to help trace the operation through the database profiler, currentOp and logs.

For server versions less than 4.4, only a string value may be provided.

pub fn hint(self, value: Hint) -> Self

The index to use for the operation.

pub fn max_await_time(self, value: Duration) -> Self

The maximum amount of time for the server to wait on new documents to satisfy a tailable await cursor query.

This option will have no effect on non-tailable cursors that result from this operation.

pub fn max_time(self, value: Duration) -> Self

The maximum amount of time to allow the query to run.

This options maps to the maxTimeMS MongoDB query option, so the duration will be sent across the wire as an integer number of milliseconds.

pub fn read_concern(self, value: ReadConcern) -> Self

The read concern to use for the operation.

If none is specified, the read concern defined on the object executing this operation will be used.

pub fn selection_criteria(self, value: SelectionCriteria) -> Self

The criteria used to select a server for this operation.

If none is specified, the selection criteria defined on the object executing this operation will be used.

pub fn write_concern(self, value: WriteConcern) -> Self

The write concern to use for the operation.

If none is specified, the write concern defined on the object executing this operation will be used.

pub fn let_vars(self, value: Document) -> Self

A document with any amount of parameter names, each followed by definitions of constants in the MQL Aggregate Expression language. Each parameter name is then usable to access the value of the corresponding MQL Expression with the “$$” syntax within Aggregate Expression contexts.

This feature is only available on server versions 5.0 and above.

impl<'a, T> Aggregate<'a, ImplicitSession, T>

pub fn session( self, value: impl Into<&'a mut ClientSession>, ) -> Aggregate<'a, ExplicitSession<'a>>

Use the provided session when running the operation.

impl<'a, T> Aggregate<'a, ImplicitSession, T>

pub fn run(self) -> Result<Cursor<T>>

Available on crate feature sync only.

Synchronously execute this action.

impl<'a, T> Aggregate<'a, ExplicitSession<'a>, T>

pub fn run(self) -> Result<SessionCursor<T>>

Available on crate feature sync only.

Synchronously execute this action.

Trait Implementations

impl<'a, T> Action for Aggregate<'a, ExplicitSession<'a>, T>

fn optional<Value>( self, value: Option<Value>, f: impl FnOnce(Self, Value) -> Self, ) -> Self

where Self: Sized,

If the value is Some, call the provided function on self. Convenient for chained updates with values that need to be set conditionally. For example:

impl<'a, T> Action for Aggregate<'a, ImplicitSession, T>

fn optional<Value>( self, value: Option<Value>, f: impl FnOnce(Self, Value) -> Self, ) -> Self

where Self: Sized,

If the value is Some, call the provided function on self. Convenient for chained updates with values that need to be set conditionally. For example:

impl<'a, T> IntoFuture for Aggregate<'a, ExplicitSession<'a>, T>

type Output = Result<SessionCursor<T>, Error>

The output that the future will produce on completion.

type IntoFuture = AggregateSessionFuture<'a, T>

Which kind of future are we turning this into?

fn into_future(self) -> Self::IntoFuture

Creates a future from a value.

impl<'a, T> IntoFuture for Aggregate<'a, ImplicitSession, T>

type Output = Result<Cursor<T>, Error>

The output that the future will produce on completion.

type IntoFuture = AggregateFuture<'a, T>

Which kind of future are we turning this into?

fn into_future(self) -> Self::IntoFuture

Creates a future from a value.