CODEWITHSUNDEEP
javaspringmongodbspring-dataspring-data-mongodb
Mohit Chandani
Mohit Chandani

Reputation: 101

Convert the aggregation query of mongodb for spring boot

I have a mongodb query which works fine

db.user.aggregate([
  {
    "$project": {
      "data": {
        "$objectToArray": "$$ROOT"
      }
    }
  },
  {
    $unwind: "$data"
  },
  {
    "$match": {
      "data.v": {
        $regex: "Mohit Chandani"
      }
    }
  }
])

It basically, get all the document having the value Mohit Chandani and here is the output:

{ "_id" : "b387d728-1feb-45b6-bdec-dafdf22685e2", "data" : { "k" : "fullName", "v" : "Mohit Chandani" } }
{ "_id" : "8e35c497-4296-4ad9-8af6-9187dc0344f7", "data" : { "k" : "fullName", "v" : "Mohit Chandani" } }
{ "_id" : "c38b6767-6665-46b8-bd29-645c41d03850", "data" : { "k" : "fullName", "v" : "Mohit Chandani" } }

I need this query to be converted for my spring boot application and I am writing the following:-

Aggregation aggregation = Aggregation.newAggregation(Aggregation.project(Aggregation.ROOT), Aggregation.match(Criteria.where(connectionRequest.getWord())));

It would be helpful to know which approach to take when you do long aggregations in Spring-Data.

Upvotes: 0

Views: 5556

Answers (1)

varman
varman

Reputation: 8894

This might help you, Hope you are using MongoTemplate for aggregation.

@Autowired
private MongoTemplate mongoTemplate;

And the code for above script is

public List<Object> test() {

    Aggregation.newAggregation(
        project().and(ObjectOperators.valueOf(ROOT).toArray()).as("data"),
        unwind("data"),
        match(Criteria.where("data.v").regex("Mohit Chandani")
        )
    ).withOptions(AggregationOptions.builder().allowDiskUse(Boolean.TRUE).build());

    return mongoTemplate.aggregate(aggregation, mongoTemplate.getCollectionName(YOUR_COLLECTION.class), Object.class).getMappedResults();

}

I'm not sure the project() of above code would work, because I haven't tried it. I referred it form Spring data mongodb

If it doesn't work, this would definitely work. Few opetaiotion are not suppored in spring data like $addFields, $filter.. So we do a Trick to convert

public List<Object> test() {

    Aggregation aggregation = Aggregation.newAggregation(
        
        p-> new Document("$project",
                new Document("data",
                    new Document("$objectToArray","$$ROOT")
                )     
            ),
        unwind("data"),
        match(Criteria.where("data.v").regex("Mohit Chandani"))     

    ).withOptions(AggregationOptions.builder().allowDiskUse(Boolean.TRUE).build());

    return mongoTemplate.aggregate(aggregation, mongoTemplate.getCollectionName(YOUR_COLLECTION.class), Object.class).getMappedResults();

}

Upvotes: 1

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