Nested fields not returned in Spring Mongo DB query

Question

I have the following two documents:

@Document(collection = "projects")
public class Project {

    @Id
    private String id;
    private String name;
    @Indexed(unique = true)
    private String slug;

    private List<Component> components;
    private List<Feature> features;
    private List<Text> texts;

    // constructors, getters and setters omitted
}

And:

public class Text {

    private String key;
    private String defaultText;
    private String comment;

    private String featureUsing;
    private List<String> componentsUsing;

    // constructors, getters and setters omitted

}

Basically I have an array of texts inside a project.

Currently this is the only document I have:

{
    "_class": "org.aribeiro.i18n.entities.Project",
    "_id": "5a64b8b65aa0334ada6eced6",
    "components": [
        {
            "name": "Find and Ring portal",
            "slug": "find-and-ring-portal"
        }
    ],
    "features": [
        {
            "name": "Find and Ring",
            "slug": "find-and-ring"
        }
    ],
    "name": "Project 2",
    "slug": "project-2",
    "texts": [
        {
            "comment": "This is to show the title",
            "componentsUsing": [
                "find-and-ring-portal"
            ],
            "defaultText": "Find and Ring",
            "featureUsing": "find-and-ring",
            "key": "findringportal.title"
        }
    ]
}

I want to get only the texts part that match the following filter:

{'texts.key': 'findringportal.title' }

So I configured this query in my TextsRepository:

@Query(value = "{'texts.key': ?0 }", fields = "{ 'texts.key' : 1, 'texts.defaultText': 1 }")
Text findByKey(String key);

TextsRepository is:

public interface TextsRepository extends MongoRepository<Text, String> {

    @Query(value = "{'texts.key': ?0 }", fields = "{ 'texts.key' : 1, 'texts.defaultText': 1 }")
    Text findByKey(String key);

}

Problem is that when executing that query I get a null. The only way to get some data is by making it return a Project instance and only the fields defined are returned. But isn't there a way to make it marshal to the nested entities?

pvpkiran · Accepted Answer · 2018-01-21 17:09:56Z

1

Couple of points

Problem is that when executing that query I get a null. --> Ofcourse you will get null because your repository is TextsRepository, which will look for collection called texts in database which it cannot find.
You have only projects collection in database

@Document(collection = "projects")

Your Query is correct, but you should be executing this against ProjectRepository.

public interface ProjectRepository extends MongoRepository<Project, String> {

    @Query(value = "{'texts.key': ?0 }", fields = "{ 'texts.key' : 1, 'texts.defaultText': 1 }")
    Project findByKey(String key);   
}

The return type of the query method should be assignable to the managed domain type(in your case Project).

answered Jan 21, 2018 at 17:09

pvpkiran

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1 Comment

Miguel Ribeiro Over a year ago

I thought I didn't end up submitting this question! I quickly learnt it short after posting. Thanks !

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