1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
|
// 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/options/find.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 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;
}
|
