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Connect to MongoDB

Create a MongoDB Client

On this page

  • Overview
  • Connection URI
  • Create a mongocxx::client
  • API Documentation

Overview

To connect to a MongoDB deployment, you need two things:

  • A connection URI, also known as a connection string, which tells the C++ driver which MongoDB deployment to connect to.

  • A mongocxx::client object, which creates the connection to the MongoDB deployment and lets you perform operations on it.

You can also use either of these components to customize the way the C++ driver behaves while connected to MongoDB.

This guide shows you how to create a connection string and use a mongocxx::client object to connect to MongoDB.

Note

mongocxx::instance

The code examples on this page assume that you've already created a mongocxx::instance object elsewhere in your application.

To learn more about creating an instance, see Create a Driver Instance.

Connection URI

A standard connection string includes the following components:

Component
Description
mongodb://
Required. A prefix that identifies this as a string in the standard connection format.
db_username:db_password
Optional. Authentication credentials. If you include these, the client authenticates the user against the database specified in authSource. For more information about the authSource connection option, see Authentication Mechanisms.
host[:port]
Required. The host and optional port number where MongoDB is running. If you don't include the port number, the driver uses the default port, 27017.
/defaultauthdb
Optional. The authentication database to use if the connection string includes db_username:db_password@ authentication credentials but not the authSource option. If you don't include this component, the client authenticates the user against the admin database.
?<options>
Optional. A query string that specifies connection-specific options as <name>=<value> pairs. See Specify Connection Options for a full description of these options.

For more information about creating a connection string, see Connection Strings in the MongoDB Server documentation.

Create a mongocxx::client

To create a connection to MongoDB, construct an instance of the mongocxx::uri class, passing the connection URI as a string to the constructor. Then, pass the instance of the mongocxx::uri class to the mongocxx::client constructor.

In the following example, the driver uses a sample connection URI to connect to a MongoDB deployment on port 27017 of localhost:

#include <mongocxx/instance.hpp>
#include <mongocxx/uri.hpp>
#include <mongocxx/client.hpp>
int main()
{
    mongocxx::instance instance;
    mongocxx::uri uri("mongodb://localhost:27017");
    mongocxx::client client(uri);
}

Tip

Reuse Your Client

Because each mongocxx::client object represents a pool of connections to the database, most applications require only a single instance of mongocxx::client, even across multiple requests.

API Documentation

To learn more about creating a mongocxx::client object in C++ driver, see the following API documentation:

Back

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