title: How to unset field for loads of documents?
body: <p>I have huge table that is fully dynamic (not mapped to any POCO). It has multiple fields and one of them is named <code>two</code>. How can I remove this field for every document that has <code>ArchiveId</code> set to <code>1</code>?</p>
  
  <p>I have tried getting all items and then saving each but it gives me error. I suspect that db just times out or something because it's working and running since I can get records just fine afterwards.</p>
  
  <p>Note that I have over 1m records and this method that I'm doing is probably very bad but I don't know any better.</p>
  
  <blockquote>
    <p>Server instance localhost:27017 is no longer connected.</p>
  </blockquote>
  
  <p>What I have tried</p>
  
  <pre><code>public void DeleteFieldByArchiveId(int id, string field)
  {
      var collection = _db.GetCollection("items");
  
      collection.Find(Query.EQ("ArchiveId", id))
          .ToList()
          .ForEach(x =&gt;
          {
              x[field] = null;
              collection.Save(x);
          });
  }
  </code></pre>
  
  <h1>EDIT (What I need)</h1>
  
  <p><code>db.items.update({ArchiveId: 1}, {$unset: {two : ""}}, {multi: true})</code></p>
  
  <p>Basically this is what I want to achieve using C# mongo driver. I just tested this query in RoboMongo and it removed all fields from 1m database in about 20 seconds without timeouts. How can I execute this query inside C# mongo driver?</p>