Updating a specific doc in array in subdocument in MongoDb

Question

I have a document user that have a schema as:

{
    "_id" : ObjectId("57b2d706f61d04e8d99dd983"),
    "addressesAsVendor" : [ 
        {
            "_id" : "V1",
            "addressLine1" : "al1",
            "addressLine2" : "al2",
            "street" : "street",
            "city" : "city",
            "country" : "IN",
            "pincode" : "490020",
            "location" : {
                "latitutde" : "lat1",
                "longitude" : "lon1"
            }
        }, 
        {
            "_id" : "V2",
            "addressLine1" : "al1",
            "addressLine2" : "al2",
            "street" : "street",
            "city" : "city",
            "country" : "IN",
            "pincode" : "490020",
            "location" : {
                "latitutde" : "lat2",
                "longitude" : "lon2"
            }
        }
    ]
}

Now let's suppose I want to update the V1 id of the addressesAsVendor array which is inside the user Id 57b2d706f61d04e8d99dd983 with the data:

{
    "addressLine1" : "al1 new",
    "addressLine2" : "al2 new",
    "street" : "street new",
    "city" : "city new",
    "country" : "IN new",
    "pincode" : "490020 new",
    "location" : {
       "latitutde" : "lat1 new",
       "longitude" : "lon1 new"
    }
}

So the new user doc will look like:

{
    "_id" : ObjectId("57b2d706f61d04e8d99dd983"),
    "addressesAsVendor" : [ 
        {
            "_id" : "V1",
            "addressLine1" : "al1 new",
            "addressLine2" : "al2 new",
            "street" : "street new",
            "city" : "city new",
            "country" : "IN new",
            "pincode" : "490020 new",
            "location" : {
              "latitutde" : "lat1 new",
              "longitude" : "lon1 new"
            }
        }, 
        {
            "_id" : "V2",
            "addressLine1" : "al1",
            "addressLine2" : "al2",
            "street" : "street",
            "city" : "city",
            "country" : "IN",
            "pincode" : "490020",
            "location" : {
                "latitutde" : "lat2",
                "longitude" : "lon2"
            }
        }
    ]
}

How this can be achieved in MongoDb and what's the best way of keeping multiple addresses, which can be easily shown in the Address page of the user and also minimum in load, I mean will be easy to access when required.

Please shed your views. :)

Answer 1

You can do the update using the positional $ operator:

var data = {
    "addressLine1" : "al1 new",
    "addressLine2" : "al2 new",
    "street" : "street new",
    "city" : "city new",
    "country" : "IN new",
    "pincode" : "490020 new",
    "location" : {
       "latitutde" : "lat1 new",
       "longitude" : "lon1 new"
    }
};

collection.update(
    { "addressesAsVendor._id" : "V1" },
    { "$set": { "addressesAsVendor.$": data  } }, 
    function(err, result) {
         if (err) return handleError(err);
         console.log(result);
    }
)

The positional operator in the above saves the index (0 in the case above) of the element from the array that matched the query. This means that if you knew the position of the element beforehand (which is nearly impossible in a real life case), you could just change the update statement to: { "$set": { "addressesAsVendor.0": data } }.

Since the positional $ operator acts as a placeholder for the first element that matches the query document, and the array field must appear as part of the query document hence the query { "addressesAsVendor._id" : "V1" } is essential to get the $ operator to work properly.

Please note that the positional $ operator (for now) updates the first relevant document ONLY, there is a JIRA ticket for this.

---

For your follow-up question which seeks to find the best way of keeping multiple addresses, which can be easily shown in the Address page of the user and also minimum in load:

Your current schema is a better approach than creating a separate collection of addresses since separate collections require more work i.e. finding a user + its addresses is two queries and requires extra work whereas the above schema embedded documents are easy and fast (single seek). There are no big differences for inserts and updates. So, separate collections are good if you need to select individual documents, need more control over querying, or have huge documents. Embedded documents are good when you want the entire document, the document with a $slice of the embedded addressesAsVendor, or with no addresses at all.

As a general rule, if you have a lot of "addresses" or if they are large, a separate collection might be best.

Smaller and/or fewer documents tend to be a natural fit for embedding.

Answer 2

You can use updateOne (MongoDB query) to update the document.

NodeJS equivalent is:-

collection.update(criteria, update[[, options], callback]);

Please change the object id accordingly.

db.address.updateOne({ "_id" : ObjectId("57c04425c400a6b59c9bc1ee"), "addressesAsVendor._id" : "V1" }, { $set: { "addressesAsVendor.$.addressLine1" : "al1 new", 
   "addressesAsVendor.$.addressLine2" : "al2 new",
            "addressesAsVendor.$.street" : "street new",
            "addressesAsVendor.$.city" : "city new",
            "addressesAsVendor.$.country" : "IN new",
            "addressesAsVendor.$.pincode" : "490020 new",
            "addressesAsVendor.$.location" : {
              "latitutde" : "lat1 new",
              "longitude" : "lon1 new"
            }
    } });