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query_projection.cpp
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query_projection.cpp
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// Copyright 2017 MongoDB Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <iostream>
#include <bsoncxx/builder/basic/document.hpp>
#include <bsoncxx/builder/basic/kvp.hpp>
#include <bsoncxx/json.hpp>
#include <mongocxx/client.hpp>
#include <mongocxx/instance.hpp>
#include <mongocxx/options/find.hpp>
#include <mongocxx/uri.hpp>
using bsoncxx::builder::basic::kvp;
using bsoncxx::builder::basic::make_document;
int main(int, char**) {
// The mongocxx::instance constructor and destructor initialize and shut down the driver,
// respectively. Therefore, a mongocxx::instance must be created before using the driver and
// must remain alive for as long as the driver is in use.
mongocxx::instance inst{};
mongocxx::client conn{mongocxx::uri{}};
auto coll = conn["test"]["query_projection"];
coll.drop();
// Insert a test document
auto result =
coll.insert_one(make_document(kvp("user info", make_document(kvp("user name", "Joe")))));
std::cout << "Inserted " << result->inserted_id().get_oid().value.to_string() << std::endl;
// Create the find options with the projection
mongocxx::options::find opts{};
opts.projection(make_document(kvp("_id", 1)));
// Execute find with options
auto cursor = coll.find(make_document(kvp("user info.user name", "Joe")), opts);
for (auto&& doc : cursor) {
std::cout << bsoncxx::to_json(doc) << std::endl;
}
return EXIT_SUCCESS;
}