find in BSON documents with MongoDB C++ driver

问题

I have the following document in my MongoDB test database:

  db.a.find()
       {[ {
            "_id" : ObjectId("5113d680732fb764c44qweq"),
            "Builds" : [
                    {
                        "level" : 1,
                        "rank" : 2
                    },
                    {
                        "level" : 3,
                        "rank" : 4
                    }
                  ],
  "abs" : [
                    {
                        "level" : 3,
                        "status" : 5
                    },
                    {
                        "level" : 3,
                        "status" : 4
                    }
                  ]
    }, {
     "_id" : ObjectId("5113d680732fb764c4464fdf"),
            "Builds" : [
                    {
                        "level" : 3,
                        "rank" : 5
                    },
                    {
                        "level" : 3,
                        "rank" : 4
                    }
                  ],
    "abs" : [
                    {
                        "level" : 3,
                        "status" : 5
                    },
                    {
                        "level" : 3,
                        "status" : 4
                    }
                  ]
        }
    ]}

I need find Builds level >=2 and <= 5 and abs status >=5 it like if(builds.leve >=2 && builds.level <= 5 && abs.status >=5 && abs.level>=2) multiple conditions and need take a size of values May you help me?

回答1:

Here is an sample for you. I am not much into mongo cxx so i am not sure about the syntax.

bsoncxx::builder::stream::document filter_builder;
filter_builder << "$or" << "Builds.level" 
    << open_document << "$gte" << 1 << "$lte" << 5 << close_document
    << open_document << "abs.status" << "$gte" << 2 << "$lte" << 5 
        << close_document << close_array;

auto cursor = db["your collection name"].find(filter_builder.view());
for (auto&& doc : cursor) {
    std::cout << bsoncxx::to_json(doc) << std::endl;
}

来源：https://stackoverflow.com/questions/40998609/find-in-bson-documents-with-mongodb-c-driver