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Esercizi Lettura MongoDB C++

Ecco degli esercizi semplici con soluzione per praticare la lettura di dati in MongoDB utilizzando C++ sia in modo sequenziale che OOP.

Esercizio 1: Lettura di un singolo documento usando mongocxx (metodo sequenziale)

Stabilire una connessione a MongoDB e leggere un singolo documento.

#include <mongocxx/client.hpp>
#include <mongocxx/instance.hpp>
#include <mongocxx/uri.hpp>
#include <bsoncxx/json.hpp>
#include <bsoncxx/builder/basic/document.hpp>
#include <iostream>

int main() {
    mongocxx::instance instance{};
    mongocxx::client client{mongocxx::uri{"mongodb://localhost:27017"}};
    auto collection = client["test_db"]["test_collection"];

    bsoncxx::builder::basic::document filter{};
    filter.append(bsoncxx::builder::basic::kvp("name", "John Doe"));

    auto result = collection.find_one(filter.view());
    if (result) {
        std::cout << bsoncxx::to_json(*result) << std::endl;
    } else {
        std::cout << "Documento non trovato" << std::endl;
    }

    return 0;
}

Esercizio 2: Lettura di più documenti usando mongocxx (metodo sequenziale)

Stabilire una connessione a MongoDB e leggere più documenti.

#include <mongocxx/client.hpp>
#include <mongocxx/instance.hpp>
#include <mongocxx/uri.hpp>
#include <bsoncxx/json.hpp>
#include <bsoncxx/builder/basic/document.hpp>
#include <iostream>

int main() {
    mongocxx::instance instance{};
    mongocxx::client client{mongocxx::uri{"mongodb://localhost:27017"}};
    auto collection = client["test_db"]["test_collection"];

    bsoncxx::builder::basic::document filter{};
    filter.append(bsoncxx::builder::basic::kvp("status", "active"));

    auto cursor = collection.find(filter.view());
    for (auto&& doc : cursor) {
        std::cout << bsoncxx::to_json(doc) << std::endl;
    }

    return 0;
}

Esercizio 3: Lettura di un singolo documento usando mongocxx (OOP)

Creare una classe per gestire la connessione a MongoDB e leggere un singolo documento.

#include <mongocxx/client.hpp>
#include <mongocxx/instance.hpp>
#include <mongocxx/uri.hpp>
#include <bsoncxx/json.hpp>
#include <bsoncxx/builder/basic/document.hpp>
#include <iostream>

class MongoDBClient {
private:
    mongocxx::instance instance{};
    mongocxx::client client{mongocxx::uri{"mongodb://localhost:27017"}};
public:
    MongoDBClient() = default;

    void leggiDocumento(const std::string& db_name, const std::string& coll_name, const bsoncxx::document::view& filter) {
        auto collection = client[db_name][coll_name];
        auto result = collection.find_one(filter);
        if (result) {
            std::cout << bsoncxx::to_json(*result) << std::endl;
        } else {
            std::cout << "Documento non trovato" << std::endl;
        }
    }
};

int main() {
    MongoDBClient client;
    bsoncxx::builder::basic::document filter{};
    filter.append(bsoncxx::builder::basic::kvp("name", "John Doe"));
    client.leggiDocumento("test_db", "test_collection", filter.view());
    return 0;
}

Esercizio 4: Lettura di più documenti usando mongocxx (OOP)

Creare una classe per gestire la connessione a MongoDB e leggere più documenti.

#include <mongocxx/client.hpp>
#include <mongocxx/instance.hpp>
#include <mongocxx/uri.hpp>
#include <bsoncxx/json.hpp>
#include <bsoncxx/builder/basic/document.hpp>
#include <iostream>

class MongoDBClient {
private:
    mongocxx::instance instance{};
    mongocxx::client client{mongocxx::uri{"mongodb://localhost:27017"}};
public:
    MongoDBClient() = default;

    void leggiDocumenti(const std::string& db_name, const std::string& coll_name, const bsoncxx::document::view& filter) {
        auto collection = client[db_name][coll_name];
        auto cursor = collection.find(filter);
        for (auto&& doc : cursor) {
            std::cout << bsoncxx::to_json(doc) << std::endl;
        }
    }
};

int main() {
    MongoDBClient client;
    bsoncxx::builder::basic::document filter{};
    filter.append(bsoncxx::builder::basic::kvp("status", "active"));
    client.leggiDocumenti("test_db", "test_collection", filter.view());
    return 0;
}

Esercizio 5: Lettura di un singolo documento usando mongo-c-driver (metodo sequenziale)

Stabilire una connessione a MongoDB e leggere un singolo documento usando mongo-c-driver.

#include <mongoc/mongoc.h>
#include <bson/bson.h>
#include <iostream>

int main() {
    mongoc_init();

    mongoc_client_t *client = mongoc_client_new("mongodb://localhost:27017");
    mongoc_collection_t *collection = mongoc_client_get_collection(client, "test_db", "test_collection");

    bson_t *filter = BCON_NEW("name", BCON_UTF8("John Doe"));
    mongoc_cursor_t *cursor = mongoc_collection_find_with_opts(collection, filter, nullptr, nullptr);

    const bson_t *doc;
    if (mongoc_cursor_next(cursor, &doc)) {
        char *str = bson_as_canonical_extended_json(doc, nullptr);
        std::cout << str << std::endl;
        bson_free(str);
    } else {
        std::cout << "Documento non trovato" << std::endl;
    }

    bson_destroy(filter);
    mongoc_cursor_destroy(cursor);
    mongoc_collection_destroy(collection);
    mongoc_client_destroy(client);
    mongoc_cleanup();

    return 0;
}

Esercizio 6: Lettura di più documenti usando mongo-c-driver (metodo sequenziale)

Stabilire una connessione a MongoDB e leggere più documenti usando mongo-c-driver.

#include <mongoc/mongoc.h>
#include <bson/bson.h>
#include <iostream>

int main() {
    mongoc_init();

    mongoc_client_t *client = mongoc_client_new("mongodb://localhost:27017");
    mongoc_collection_t *collection = mongoc_client_get_collection(client, "test_db", "test_collection");

    bson_t *filter = BCON_NEW("status", BCON_UTF8("active"));
    mongoc_cursor_t *cursor = mongoc_collection_find_with_opts(collection, filter, nullptr, nullptr);

    const bson_t *doc;
    while (mongoc_cursor_next(cursor, &doc)) {
        char *str = bson_as_canonical_extended_json(doc, nullptr);
        std::cout << str << std::endl;
        bson_free(str);
    }

    bson_destroy(filter);
    mongoc_cursor_destroy(cursor);
    mongoc_collection_destroy(collection);
    mongoc_client_destroy(client);
    mongoc_cleanup();

    return 0;
}

Esercizio 7: Lettura di un singolo documento usando mongo-c-driver (OOP)

Creare una classe per gestire la connessione a MongoDB e leggere un singolo documento usando mongo-c-driver.

#include <mongoc/mongoc.h>
#include <bson/bson.h>
#include <iostream>

class MongoDBClient {
private:
    mongoc_client_t *client;
public

:
    MongoDBClient(const std::string& uri) {
        mongoc_init();
        client = mongoc_client_new(uri.c_str());
    }

    ~MongoDBClient() {
        mongoc_client_destroy(client);
        mongoc_cleanup();
    }

    void leggiDocumento(const std::string& db_name, const std::string& coll_name, const bson_t* filter) {
        mongoc_collection_t *collection = mongoc_client_get_collection(client, db_name.c_str(), coll_name.c_str());
        mongoc_cursor_t *cursor = mongoc_collection_find_with_opts(collection, filter, nullptr, nullptr);

        const bson_t *doc;
        if (mongoc_cursor_next(cursor, &doc)) {
            char *str = bson_as_canonical_extended_json(doc, nullptr);
            std::cout << str << std::endl;
            bson_free(str);
        } else {
            std::cout << "Documento non trovato" << std::endl;
        }

        mongoc_cursor_destroy(cursor);
        mongoc_collection_destroy(collection);
    }
};

int main() {
    MongoDBClient client("mongodb://localhost:27017");

    bson_t *filter = BCON_NEW("name", BCON_UTF8("John Doe"));
    client.leggiDocumento("test_db", "test_collection", filter);
    bson_destroy(filter);

    return 0;
}

Esercizio 8: Lettura di più documenti usando mongo-c-driver (OOP)

Creare una classe per gestire la connessione a MongoDB e leggere più documenti usando mongo-c-driver.

#include <mongoc/mongoc.h>
#include <bson/bson.h>
#include <iostream>

class MongoDBClient {
private:
    mongoc_client_t *client;
public:
    MongoDBClient(const std::string& uri) {
        mongoc_init();
        client = mongoc_client_new(uri.c_str());
    }

    ~MongoDBClient() {
        mongoc_client_destroy(client);
        mongoc_cleanup();
    }

    void leggiDocumenti(const std::string& db_name, const std::string& coll_name, const bson_t* filter) {
        mongoc_collection_t *collection = mongoc_client_get_collection(client, db_name.c_str(), coll_name.c_str());
        mongoc_cursor_t *cursor = mongoc_collection_find_with_opts(collection, filter, nullptr, nullptr);

        const bson_t *doc;
        while (mongoc_cursor_next(cursor, &doc)) {
            char *str = bson_as_canonical_extended_json(doc, nullptr);
            std::cout << str << std::endl;
            bson_free(str);
        }

        mongoc_cursor_destroy(cursor);
        mongoc_collection_destroy(collection);
    }
};

int main() {
    MongoDBClient client("mongodb://localhost:27017");

    bson_t *filter = BCON_NEW("status", BCON_UTF8("active"));
    client.leggiDocumenti("test_db", "test_collection", filter);
    bson_destroy(filter);

    return 0;
}