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// Copyright 2009-present 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/pipeline.hpp>
#include <mongocxx/uri.hpp>
#include <examples/macros.hh>
using bsoncxx::builder::basic::kvp;
using bsoncxx::builder::basic::make_document;
int EXAMPLES_CDECL main() {
// 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 db = conn["test"];
// Group documents by field and calculate count.
{
mongocxx::pipeline stages;
stages.group(
make_document(kvp("_id", "$borough"), kvp("count", make_document(kvp("$sum", 1)))));
auto cursor = db["restaurants"].aggregate(stages);
for (auto&& doc : cursor) {
std::cout << bsoncxx::to_json(doc) << std::endl;
}
}
// Filter and group documents.
{
mongocxx::pipeline stages;
stages.match(make_document(kvp("borough", "queens"), kvp("cuisine", "Brazilian")))
.group(make_document(kvp("_id", "$address.zipcode"),
kvp("count", make_document(kvp("$sum", 1)))));
auto cursor = db["restaurants"].aggregate(stages);
for (auto&& doc : cursor) {
std::cout << bsoncxx::to_json(doc) << std::endl;
}
}
}
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