How can I remove a document from an array?

Question

I have inserted a document with this structure

{ 
  "_id" : ObjectId("5708bf40a86e6f5bd1f45354"),
  "companyId" : ObjectId("5708bed6a86e6f5bd1f4534f"),
  "descriptions" : [ 
       { "id" : ObjectId("5708bf40a86e6f5bd1f45351"), "description" : "test" },
       { "id" : ObjectId("5708bf40a86e6f5bd1f45352"), "description" : "test1" },
       { "id" : ObjectId("5708bf40a86e6f5bd1f45353"), "description" : "test2" } 
   ]
}

and now I'm trying to modify the array by removing an object which is matching some criteria - in this case I need to remove the object with a specific id.

Here is what I'm doing so far, without any success

public void deleteCustomField(final String descriptionId, final ObjectId companyId){
    MongoCollection<Document> collection = setCollection(CUSTOM_FIELDS_COLLECTION);

    collection.updateOne(and(eq("companyId", companyId), eq("descriptions.id", new ObjectId(descriptionId))), new Document("$unset", new Document("descriptions.description", "")));
}

This is the setCollection method

private MongoCollection<Document> setCollection(final String collectionName){
    return db.getCollection(collectionName); 
}

The updateOne does nothing at all. I know that my query is looking strange, but I can't understand what is going on and how to remove the document from the array. I also tried with $pull but I had no luck at all.

I know that I'm missing something small and really basic here, but as a MongoDB beginner, I'm not able to spot it.

Can you give me a push?

Answer 1

You may try to replace new Document("$unset", new Document("descriptions.description", "")) by new Document("$pull", new Document("descriptions.id", new ObjectId(descriptionId))). See the doc for the pull operator.