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DATAMONGO-2331 - Add support for Update with an aggregation pipeline.

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Now the update methods exposed by (Reactive)MongoOperations also accept an Aggregation Pipeline via AggregationUpdate.

The update can consist of the following stages:

* AggregationUpdate.set(...).toValue(...) -> $set : { ... }
* AggregationUpdate.unset(...) -> $unset : [ ... ]
* AggregationUpdate.replaceWith(...) -> $replaceWith : { ... }

AggregationUpdate update = Aggregation.newUpdate()
    .set("average").toValue(ArithmeticOperators.valueOf("tests").avg())
    .set("grade").toValue(ConditionalOperators.switchCases(
        when(valueOf("average").greaterThanEqualToValue(90)).then("A"),
        when(valueOf("average").greaterThanEqualToValue(80)).then("B"),
        when(valueOf("average").greaterThanEqualToValue(70)).then("C"),
        when(valueOf("average").greaterThanEqualToValue(60)).then("D"))
        .defaultTo("F")
    );

template.update(Student.class)
    .apply(update)
    .all();

Original pull request: #789.
This commit is contained in:
Christoph Strobl
2019-09-17 08:31:55 +02:00
committed by Mark Paluch
parent 9eaf67148d
commit 32cbae0e5f
25 changed files with 2981 additions and 158 deletions
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55
src/main/asciidoc/reference/mongodb.adoc
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@@ -996,6 +996,61 @@ assertThat(p.getFirstName(), is("Mary"));
assertThat(p.getAge(), is(1));
----
[[mongo-template.aggregation-update]]
=== Aggregation Pipeline Updates
The update methods exposed by `MongoOperations` and `ReactiveMongoOperations` also accept an <<mongo.aggregation, Aggregation Pipeline>> via `AggregationUpdate`.
This allows to leverage https://docs.mongodb.com/manual/reference/method/db.collection.update/#update-with-aggregation-pipeline[MongoDB 4.2 aggregations] in an update operation.
The update can consist of the following stages:
* `AggregationUpdate.set(...).toValue(...)` -> `$set : { ... }`
* `AggregationUpdate.unset(...)` -> `$unset : [ ... ]`
* `AggregationUpdate.replaceWith(...)` -> `$replaceWith : { ... }`
.Update Aggregation
====
[source,java]
----
AggregationUpdate update = Aggregation.newUpdate()
.set("average").toValue(ArithmeticOperators.valueOf("tests").avg()) <1>
.set("grade").toValue(ConditionalOperators.switchCases( <2>
when(valueOf("average").greaterThanEqualToValue(90)).then("A"),
when(valueOf("average").greaterThanEqualToValue(80)).then("B"),
when(valueOf("average").greaterThanEqualToValue(70)).then("C"),
when(valueOf("average").greaterThanEqualToValue(60)).then("D"))
.defaultTo("F")
);
template.update(Student.class) <3>
.apply(update)
.all(); <4>
----
[source,javascript]
----
db.students.update( <3>
{ },
[
{ $set: { average : { $avg: "$tests" } } }, <1>
{ $set: { grade: { $switch: { <2>
branches: [
{ case: { $gte: [ "$average", 90 ] }, then: "A" },
{ case: { $gte: [ "$average", 80 ] }, then: "B" },
{ case: { $gte: [ "$average", 70 ] }, then: "C" },
{ case: { $gte: [ "$average", 60 ] }, then: "D" }
],
default: "F"
} } } }
],
{ multi: true } <4>
)
----
<1> The 1st `$set` stage calculates a new field _average_ based on the average of the _tests_ field.
<2> The 2nd `$set` stage calculates a new field _grade_ based on the _average_ field calculated by the first aggregation stage.
<3> The pipeline is executed on the _students_ collection and uses `Student` for the aggregation field mapping.
<4> Apply the update to all documents within the collection.
====
[[mongo-template.find-and-replace]]
=== Finding and Replacing Documents