C# - MongoDB - Update an element inside a Nested Document

Question

I have a MongoDB Document as follows

{
"_id" : ObjectId("5a55775cbd12982cc063c71a"),
"ShipmentNumber" : "00004000000048652254",
"Cartons" : [ 
    {
        "_id" : ObjectId("5a5575bcbd12982cc063b718"),
        "CartonNumber" : "0076013926580S",
        "Skus" : [ 
            {
                "_id" : ObjectId("5a5575bcbd12982cc063b719"),
                "SkuNumber" : "06577647",
                "ShippedQuantity" : 12,
            },
            {
                "_id" : ObjectId("5a5575bcbd12982cc063b519"),
                "SkuNumber" : "06577657",
                "ShippedQuantity" : 15,
            }
        ],
        "IsScanned" : false,
    },
}

How can I update the "ShippedQuantity" for a particular Sku element based on its "_id" in C# code ?

I tried something like below. But it is not working. Getting error message like

cannot use the part (Cartons of Cartons.$[].Skus.$.ShippedQuantity) to traverse the element

var filter = Builders<BsonDocument>.Filter.Eq("Cartons.Skus._id", new ObjectId("5a5575bcbd12982cc063b519"));
var update = Builders<BsonDocument>.Update.Set("Cartons.$[].Skus.$.ShippedQuantity", 50)

I am facing difficulties when I try to update multi level documents. (In this case I have a list of Cartons and each carton will have its own list of skus and I need to update a specific sku's element)

Please provide a solution or alternative approach to update this inner level (more than 2 levels) documents in MongoDB using C#.

I updated my MongoDB server to the latest 3.6.1. But that is also not helping.

Thanks for your help.

Answer 1

First, you need to run this command in your MongoDB to apply the new features of version 3.6.1 db.adminCommand( { setFeatureCompatibilityVersion: "3.6" } )

Here is the code you need for that update:

var filter = Builders<YOUR_CLASS>.Filter.Eq("_id", new ObjectId("5a55775cbd12982cc063c71a"));
var update = Builders<YOUR_CLASS>.Update.Set("Cartons.$[i].Skus.$[j].ShippedQuantity", 50);

var arrayFilters = new List<ArrayFilterDefinition>
{
    new BsonDocumentArrayFilterDefinition<Setup>(new BsonDocument("i._id", new ObjectId("5a5575bcbd12982cc063b718"))),
    new BsonDocumentArrayFilterDefinition<Setup>(new BsonDocument("j._ID", new ObjectId("5a5575bcbd12982cc063b719")))
};
var updateOptions = new UpdateOptions { ArrayFilters = arrayFilters };
var (updated, errorMessage) = await UpdateOneAsync(filter, update, updateOptions);

Additionally, you can run set these settings in your MongoDB to look at your final queries and run them manually in RoboMongo or Studio 3T to debug them:

db.setProfilingLevel(2)   -> to view query logs under C:\data\log\mongod.log
db.setLogLevel(5)         -> to view query logs under C:\data\log\mongod.log

look for the "UPDATE" query in the log file. After that, you can reset the log setting back to 0

db.setProfilingLevel(0)
db.setLogLevel(0)

I've had the same problem and asked the same question Here Have a look at it.