title: Modifying bson documents with mongodb c# and c++ drivers
body: <p>In the c# mongodb driver (version 2.3) it is very easy to <a href="http://mongodb.github.io/mongo-csharp-driver/2.3/apidocs/html/M_MongoDB_Bson_BsonDocument_Set_1.htm" rel="nofollow noreferrer">modify</a> an existing bson document. However, the c++ driver (version v3) seems to provide only a read-only view of a existing document or the builder for new documents. Did I overlook some features of the c++ driver or does the c++ driver really miss the modify functionality or does the c# driver just simulated the modification by internally copying the original document and adding the modification into the new document?</p>