Question

I am trying to insert nested documents in to a MongoDB using C#. I have a collection called categories. In that collection there must exist documents with 2 array, one named categories and one named standards. Inside those arrays must exist new documents with their own ID’s that also contain arrays of the same names listed above. Below is what I have so far but I am unsure how to proceed. If you look at the code what I want to do is add the “namingConventions” document nested under the categories array in the categories document however namingConventions must have a unique ID also.

At this point I am not sure I have done any of this the best way possible so I am open to any and all advice on this entire thing.

namespace ClassLibrary1
{
using MongoDB.Bson;
using MongoDB.Driver;
public class Class1
{
       public void test()
        {
            string connectionString = "mongodb://localhost";
            MongoServer server = MongoServer.Create(connectionString);
            MongoDatabase standards = server.GetDatabase("Standards");
            MongoCollection<BsonDocument> categories = standards.GetCollection<BsonDocument>("catagories");

            BsonDocument[] batch = {
                                       new BsonDocument { { "categories", new BsonArray {} },
                                                        { "standards", new BsonArray { } }  },
                                       new BsonDocument { { "catagories", new BsonArray { } },
                                                        { "standards", new BsonArray { } }  },
                                   };
            categories.InsertBatch(batch);

            ((BsonArray)batch[0]["categories"]).Add(batch[1]);
            categories.Save(batch[0]);           
        }
    }
}

For clarity this is what I need:

What I am doing is building a coding standards site. The company wants all the standards stored in MongoDB in a tree. Everything must have a unique ID so that on top of being queried as a tree it can be queried by itself also. An example could be:

/* 0 */
{
  "_id" : ObjectId("4fb39795b74861183c713807"),
  "catagories" : [],
  "standards" : []
}

/* 1 */
{
  "_id" : ObjectId("4fb39795b74861183c713806"),
  "categories" : [{
      "_id" : ObjectId("4fb39795b74861183c713807"),
      "catagories" : [],
      "standards" : []
    }],
  "standards" : []
}

Now I have written code to make this happen but the issue seems to be that when I add object “0” to the categories array in object “1” it is not making a reference but instead copying it. This will not due because if changes are made they will be made to the original object “0” so they will not be pushed to the copy being made in the categories array, at least that is what is happening to me. I hope this clears up what I am looking for.

Answer 1

So, based on your latest comment, it seems as though this is the actual structure you are looking for:

{
    _id: ObjectId(),

    name: "NamingConventions",

    categories: [
        {
            id: ObjectId(),
            name: "Namespaces",
            standards: [
                {
                    id: ObjectId(),
                    name: "TitleCased",
                    description: "Namespaces must be Title Cased."
                },
                {
                    id: ObjectId().
                    name: "NoAbbreviations",
                    description: "Namespaces must not use abbreviations."
                }
            ]
        },
        {
            id: ObjectId(),
            name: "Variables",
            standards: [
                {
                    id: ObjectId(),
                    name: "CamelCased",
                    description: "variables must be camel cased."
                }
            ]
        }
    ]
}

Assuming this is correct, then the below is how you would insert one of these:

var collection = db.GetCollection("some collection name");

var root = new BsonDocument();
root.Add("name", "NamingConventions");
var rootCategories = new BsonArray();
rootCategories.Add(new BsonDocument
{
   { "id": ObjectId.GenerateNewId() },
   { "name", "Namespaces" },
   { "standards", new BsonArray() }
});

root.Add("categories", rootCategories);
//etc...
collection.Save(root);

Hope that helps, if not, I give up :).