Extracting some fields from an object in mongodb

Question

I am new to mongoDB and I am unable to figure out how to extract only few fields from an object in a collection.I have a collection named recipe which is as follow:-

[
  {
    "_id": "b44e864d-de8f-4110-b676-bbee13417b2e",
    "title": "Fried Eggs",
    "ingredients": [
      {
        "name": "Eggs",
        "amount": "10"
      },
      {
        "name": "Olive Oil",
        "amount": "2 tbs"
      }
    ],
    "steps": [
      "1. Heat the pan",
      "2.Add Olive Oil",
      "3. Add Eggs",
      "4. Saute"
    ],
    "comments": [
      {
        "_id": "8604e67c-2426-4742-bc91-25ee1c4064b5",
        "poster": "Ron Swanson",
        "comment": "Wrong instructions, Got stuck in Toaster"
      },
      {
        "_id": "040412bc-9046-49ca-9a65-19151b32cd91",
        "poster": "Tom Haverford",
        "comment": "What are Eggs?"
      },
      {
        "_id": "1034f082-b802-4382-be3e-ef50f07a530a",
        "poster": "Andy Dwyer",
        "comment": "What came  firsst, Eggs or Chicken"
      }
    ]
  },
  {
    "_id": "da6f9798-6547-42f5-85ed-043efabeb196",
    "title": "Boiled Eggs",
    "ingredients": [
      {
        "name": "Eggs",
        "amount": "5"
      },
      {
        "name": "Water",
        "amount": "3 Cups"
      }
    ],
    "steps": [
      "1.Boil the Water",
      "2.Add Eggs",
      "3. Keepit for 5 mins",
      "4. Let it Cool Down",
      "5. Peel off the shell"
    ],
    "comments": [
      {
        "_id": "cc569ebb-1307-499a-b9ee-7b24e557859f",
        "poster": "Ron Swanson",
        "comment": "Wrong instructions, Got stuck in Oven"
      },
      {
        "_id": "4f02756a-6e1b-4bda-a928-b3c5e03b55d8",
        "poster": "Leslie Knope",
        "comment": "What are Eggs?"
      },
      {
        "_id": "0f34a5cc-ebe3-41b5-8f0b-6d1a3c206e6b",
        "poster": "Andy Dwyer",
        "comment": "Can I remove the shell first and then boil?"
      }
    ]
  }]

I want to extract only the title and id of both the recipes when a given route is accessed. Currently,I am using this function, which return all the field of both the recipes.

var recipesCollection = db.collection("recipes");
        exports.getAllRecipes = function() {
            return recipesCollection.find({}).toArray();
        };

What query should I use to extract just the title and id of the two recipes and not all the details?

Vince Bowdren · Accepted Answer · 2016-10-24 16:22:37Z

1

As per my understanding you are trying to fetch specific fields form the mongo collection. You can achieve this just by using the projection.

var recipesCollection = db.collection("recipes");
exports.getAllRecipes = function() {
    return recipesCollection.find({}, {"title": 1}).toArray();
};

For more information follow this: https://docs.mongodb.com/v3.2/tutorial/project-fields-from-query-results/#return-the-specified-fields-and-the-id-field-only

edited Oct 24, 2016 at 16:22

Vince Bowdren

9,2853 gold badges37 silver badges61 bronze badges

answered Oct 24, 2016 at 15:41

mani

113 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Arjun Dass Over a year ago

Though i have one more question, how ddo

Collectives™ on Stack Overflow

Extracting some fields from an object in mongodb

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related