CODEWITHSUNDEEP
springmongodbspring-data-mongodb
Fırat Küçük
Fırat Küçük

Reputation: 6003

spring-data-mongodb nested document projection

I have posts collection with nested document comments. Simply document schema looks like this:

{
    "_id"     : ObjectId("5867e5e64f768509c59f9392"),
    "userId"  : 1,
    "comments": [
        {
            "id"  : 1,
            "text": "a"
        },
        {
            "id"  : 2,
            "text": "b"
        }
    ]
}

I want to project only the requested comment. I found an acceptable solution. (Only comment object return solutions are also welcome)

> db.posts.find({userId: 1, 'comments.id': 1}, {'comments.$': 1});
{ "_id" : ObjectId("5867e5e64f768509c59f9392"), "comments" : [ { "id" : 1, "text" : "a" } ] }

Then I try to apply it to mongodb repository interface with query annotation.

@Query(
    value = ""
        + "{"
        + "  'userId'     : '?1',"
        + "  'comments.id': '?2',"
        + "}",
    fields = "'comments.$'"
)
Note findComment(String userId, String commentId);

But i got cast exception. Is there a better way to do this with spring-data-mongodb?

Upvotes: 1

Views: 1260

Answers (1)

s7vr
s7vr

Reputation: 75914

Your @Query json is ill formed.

Try this.

@Query( value="{ 'userId' : ?0 , 'comments.id': ?1 }",  fields = "{ 'comments.$' : 1}")

Upvotes: 1

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