Using MongoDB from C#

A brief introduction

MongoDB drivers

• To use MongoDB from a programming language you need a driver• MongoDB has drivers for a number of languages, including• C#• Java• Node.js• PHP• http://docs.mongodb.org/ecosystem/drivers/

Visual Studio: Getting the right NuGet packages• Several MongoDB drivers for C#• I use• Official MongoDB C# driver

• The easiest way to get the driver is with NuGet• Right click you project in Visual Studio• Select Manage NuGet packages• Search for Mongo• Choose “Official MongoDB C# driver”

OOP vs. Documents

• Object Oriented Programming (C#)• Objects have a fixed schema defined by a class

• Documents (MongoDB)• Documents to not have a fixed schema

• The C# driver requires all documents to have the same structure• Fixed schema• With find(…)

• All document must have the same schema.• Otherwise you get some BSON serialization exception

• With insert(…) • If you omit some attributes they will be set to null in the document

Some methods from the driver

• MongoCursor<T> result = Collection.Find(query)• Ordinary find

• IQueryable<Book> books = from e in collection.AsQueryable() where … select e;• Find using LINQ syntax

• Collection.insert(someObject)• Inserts a new object. Giving it an ObjectId

• Collection.save(someObject)• Saves/update an existing object

• collection.Update(query, update)• Updates documents satisfying query.

• collection.Remove(query)• Removes documents satisfying query.

• WriteConcernResult• Returned by the changing methods. Has information about the status of the change

• Example• mongoBooks.cs, books2.cs (typed + un-typed examples)