Mongo++ is a library for using a Mongo database from C++. It is open sourced under the MIT license; see the LICENSE file for details.

First things first, a quick getting started:

1. Mongo++ is header only. Just copy the mongoxx/ directory to a convenient include directory, or add the repository to your include path.
2. #include <mongoxx/mongoxx.hh>
3. When compiling, you'll need to link against all of the libraries required by Mongo: -lmongoclient -lboost_system -lboost_thread-mt -lboost_filesystem -lboost_program_options

Now that that's out of the way, let's get down to the example code, which is also answers the question of "Why would I want to use Mongo++?".

Let's start with one of the great programming examples, the student grade database:

struct Student {
  std::string first_name;
  std::string last_name;
  std::vector<unsigned int> grades;
};

When using Mongo++, the first thing you'll do is define a Mapper for your datastructure(s):

using namespace mongoxx;

Mapper<Student> mapper;
mapper.add_field(&Student::first_name, "first_name"); 
mapper.add_field(&Student::last_name, "last_name"); 
mapper.add_field(&Student::grades, "grades"); 

Next, connect to a database:

Session session("localhost");

Now the fun starts. Let's imagine we need to insert students into the database:

Inserter<Student> inserter = session.inserter("students", &mapper);

Student student1, student2, student3;

inserter.insert(student1);
inserter.insert(student2);
inserter.insert(student3);

Let's query!

Get all results from the database:

std::vector<Student> students = session.query("students", &mapper).all();

Get one result from the database:

Student student = session.query("students", &mapper).one();

By now, you might be getting tired of typing "students", &mapper all over the place. The solution for this is to use a Table<> object:

Table<Student> table("localhost", mapper);

std::vector<Student> students = session.query(table).all();

Student student = session.query(table).one();

The Table<> object make filtering a query easier:

Student student = session.query(table).filter(table[&Student::first_name] == "John").filter(table[&Student::last_name] == "Doe").one();