OR in MongoDB with C# 2.2.4 driver

OR condition in MongoDB is used to check whether any of the given conditions matches. It is indicated with “|” symbol. In below Example we are fetching the records from amplecollection for which ‘Style’ key doesn’t exist or ‘style’ key doesn’t have any value.

Example:

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using MongoDB.Driver;
using MongoDB.Bson;
using MongoDB.Shared;
using MongoDB.Driver.Builders;


namespace MCNotexists
{
    public class Program
    {
      static void Main(string[] args)
      {
         string conString = "mongodb://ampleServiceQA:ampleServiceQAPassword@10.10.11.11:27017/ampleServiceQA";
         var Client = new MongoClient(conString);
         var DB = Client.GetDatabase("ampleServiceQA");
         var query = Query<ample>.NotExists(u => u.style.number);
         var builder = Builders<BsonDocument>.Filter;
         var collection = DB.GetCollection<BsonDocument>("amplecollection");
         var filter = builder.Exists("style", false) | builder.Eq("style", "");
         var RetrievedData = collection.Find(filter).ToList();
         foreach (var doc in RetrievedData)
         {
            Console.WriteLine(doc);
         }
         Console.ReadLine();
      }

        public class ample
        {
            public Style style { getset; }
        }
        public class Style
        {
            public string description { getset; }
            public string number { getset; }
        }
    }

}

Output : fetches the records from amplecollection for which ‘Style’ key doesn’t exist or ‘style’ key doesn’t have any value