Spring data mongodb - aggregation framework integration

Question

I started to use MongoDB database in my application and for data access I have chosen Spring Data for MongoDB.

I skimmed API reference and documentation and I can see that there is map-reduce integration but what about aggregation framework? I can see that it supports group by operation, which would indicate that it supports $group operator judging from this: http://docs.mongodb.org/manual/reference/sql-aggregation-comparison/, but what about other operators, are that not supported for now?

I am asking this question because I wanted to know what kind of integration with MongoDB Sping Data provides so I know what to expect, so to speak.

Ron Tuffin · Accepted Answer · 2013-08-16 07:47:21Z

8

Spring Data 1.3.0.RC1 is available and it does support the aggregation framework.

For example: The shell aggregation comand:

db.eft_transactions.aggregate(
    {$match:
        {
            service:"EFT",
            source:"MARKUP",
        }
    },
    {$group:
        {
            _id:"$card_acceptor_id",
            tran_count:{$sum:1},
            amount_sum:{$sum:"$amount"}
        }
    }
)

is run like this from java:

    AggregationOperation match = Aggregation.match(Criteria.where("service").is("EFT").and("source").is("MARKUP"));
    AggregationOperation group = Aggregation.group("card_acceptor").and("amount_sum").sum("amount").and("tran_count").count();
    Aggregation aggregation = newAggregation(match, group);
    AggregationResults<StoreSummary> result = this.mongoTemplate.aggregate(aggregation, "eft_transactions", StoreSummary.class);

The documentation is here

NOTE: We recently had to switch to using the BUILD-SNAPSHOT build of version 1.3.0. This change necessitated the change to 2 of the above lines which have changed to:

AggregationOperation group = Aggregation.group("card_acceptor").sum("amount").as("amount_sum").count().as("tran_count");
Aggregation aggregation = Aggregation.newAggregation(match, group);

edited Aug 16, 2013 at 7:47

answered Aug 8, 2013 at 12:05

Ron Tuffin

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1 Comment

devops Over a year ago

what about sample or random select? docs.mongodb.org/master/reference/operator/aggregation/sample

Ori Dar · Accepted Answer · 2013-03-25 21:48:09Z

5

The Spring Data MongoOperations.group() method is mapped to db.collection.group() MongoDB command and not the $group aggregation function. Currently there is no support in Spring Data MongoDB for aggregation framework. Map reduce, as you have mentioned, is supported though

answered Mar 25, 2013 at 21:48

Ori Dar

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1 Comment

a.b Over a year ago

You can, however, take one step down to the mongodb Java driver whenever you need powers of aggregation framework. mongoOps.getCollection("yourCollection").aggregate( ... )

Martijn Pieters · Accepted Answer · 2017-09-26 08:06:40Z

1

 Aggregation aggregation = newAggregation(
        match(Criteria.where("salesyear").is(year)),
        group("brand","salesyear").sum("numberOfCars").as("total"),
        sort(Sort.Direction.ASC, previousOperation(), "brand")    
      );

edited Sep 26, 2017 at 8:06

Martijn Pieters

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answered May 12, 2015 at 15:27

Vicky

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Comments

Pang · Accepted Answer · 2015-11-27 01:19:18Z

Here is how to get the sum of a particular field.

private Map<String, Long> getTotalMap(){
        /*
            db.pDSSummaryModel.aggregate([{
                $group: {
                    _id: null,
                    total: {
                        $sum: '$totalUniqueCustomerCount'
                    }
                }
            }])
         */
        Aggregation aggregations = newAggregation(
                group("null").sum("totalUniqueUserCount").as("userTotal")
                        .sum("totalUniqueCustomerCount").as("customerTotal"),
                project("customerTotal", "userTotal")
        );

        AggregationResults<DBObject> results = mongoTemplate.aggregate(aggregations, "pDSSummaryModel", DBObject.class);
        List<DBObject> fieldList = results.getMappedResults();
        Map<String, Long> map = new HashMap<>();
        if(fieldList != null && !fieldList.isEmpty()) {
            for(DBObject db: fieldList){
                map.put("userTotal", parseLong(db.get("userTotal").toString()));
                map.put("customerTotal", parseLong(db.get("customerTotal").toString()));
            }
        }
        return map;

    }

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