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Esercizi Modifica MySQL C++

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

Esercizio 1: Modifica di un singolo record usando MySQL Connector/C++ (metodo sequenziale)

Stabilire una connessione a MySQL e modificare un singolo record.

#include <mysql_driver.h>
#include <mysql_connection.h>
#include <cppconn/statement.h>
#include <cppconn/prepared_statement.h>
#include <iostream>

int main() {
    sql::mysql::MySQL_Driver* driver = sql::mysql::get_mysql_driver_instance();
    std::unique_ptr<sql::Connection> con(driver->connect("tcp://127.0.0.1:3306", "root", "password"));
    con->setSchema("test_db");

    std::unique_ptr<sql::PreparedStatement> pstmt(con->prepareStatement("UPDATE test_table SET age = ? WHERE name = ?"));
    pstmt->setInt(1, 35);
    pstmt->setString(2, "John Doe");
    int rows = pstmt->executeUpdate();

    std::cout << "Record modificati: " << rows << std::endl;

    return 0;
}

Esercizio 2: Modifica di più record usando MySQL Connector/C++ (metodo sequenziale)

Stabilire una connessione a MySQL e modificare più record.

#include <mysql_driver.h>
#include <mysql_connection.h>
#include <cppconn/statement.h>
#include <cppconn/prepared_statement.h>
#include <iostream>

int main() {
    sql::mysql::MySQL_Driver* driver = sql::mysql::get_mysql_driver_instance();
    std::unique_ptr<sql::Connection> con(driver->connect("tcp://127.0.0.1:3306", "root", "password"));
    con->setSchema("test_db");

    std::unique_ptr<sql::PreparedStatement> pstmt(con->prepareStatement("UPDATE test_table SET status = ? WHERE status = ?"));
    pstmt->setString(1, "inactive");
    pstmt->setString(2, "active");
    int rows = pstmt->executeUpdate();

    std::cout << "Record modificati: " << rows << std::endl;

    return 0;
}

Esercizio 3: Modifica di un singolo record usando MySQL Connector/C++ (OOP)

Creare una classe per gestire la connessione a MySQL e modificare un singolo record.

#include <mysql_driver.h>
#include <mysql_connection.h>
#include <cppconn/statement.h>
#include <cppconn/prepared_statement.h>
#include <iostream>

class MySQLClient {
private:
    sql::mysql::MySQL_Driver* driver;
    std::unique_ptr<sql::Connection> con;
public:
    MySQLClient(const std::string& host, const std::string& user, const std::string& pass, const std::string& db) {
        driver = sql::mysql::get_mysql_driver_instance();
        con.reset(driver->connect(host, user, pass));
        con->setSchema(db);
    }

    void modificaRecord(const std::string& query, int age, const std::string& name) {
        std::unique_ptr<sql::PreparedStatement> pstmt(con->prepareStatement(query));
        pstmt->setInt(1, age);
        pstmt->setString(2, name);
        int rows = pstmt->executeUpdate();
        std::cout << "Record modificati: " << rows << std::endl;
    }
};

int main() {
    MySQLClient client("tcp://127.0.0.1:3306", "root", "password", "test_db");
    client.modificaRecord("UPDATE test_table SET age = ? WHERE name = ?", 35, "John Doe");
    return 0;
}

Esercizio 4: Modifica di più record usando MySQL Connector/C++ (OOP)

Creare una classe per gestire la connessione a MySQL e modificare più record.

#include <mysql_driver.h>
#include <mysql_connection.h>
#include <cppconn/statement.h>
#include <cppconn/prepared_statement.h>
#include <iostream>

class MySQLClient {
private:
    sql::mysql::MySQL_Driver* driver;
    std::unique_ptr<sql::Connection> con;
public:
    MySQLClient(const std::string& host, const std::string& user, const std::string& pass, const std::string& db) {
        driver = sql::mysql::get_mysql_driver_instance();
        con.reset(driver->connect(host, user, pass));
        con->setSchema(db);
    }

    void modificaRecords(const std::string& query, const std::string& new_status, const std::string& old_status) {
        std::unique_ptr<sql::PreparedStatement> pstmt(con->prepareStatement(query));
        pstmt->setString(1, new_status);
        pstmt->setString(2, old_status);
        int rows = pstmt->executeUpdate();
        std::cout << "Record modificati: " << rows << std::endl;
    }
};

int main() {
    MySQLClient client("tcp://127.0.0.1:3306", "root", "password", "test_db");
    client.modificaRecords("UPDATE test_table SET status = ? WHERE status = ?", "inactive", "active");
    return 0;
}

Esercizio 5: Modifica di un singolo record usando MySQL C API (metodo sequenziale)

Stabilire una connessione a MySQL e modificare un singolo record usando MySQL C API.

#include <mysql/mysql.h>
#include <iostream>

int main() {
    MYSQL* conn = mysql_init(nullptr);
    if (conn == nullptr) {
        std::cerr << "mysql_init() failed\n";
        return EXIT_FAILURE;
    }

    if (mysql_real_connect(conn, "localhost", "root", "password", "test_db", 0, nullptr, 0) == nullptr) {
        std::cerr << "mysql_real_connect() failed\n";
        mysql_close(conn);
        return EXIT_FAILURE;
    }

    const char* query = "UPDATE test_table SET age = 35 WHERE name = 'John Doe'";
    if (mysql_query(conn, query)) {
        std::cerr << "UPDATE failed. Error: " << mysql_error(conn) << std::endl;
    } else {
        std::cout << "Record modificato con successo." << std::endl;
    }

    mysql_close(conn);
    return EXIT_SUCCESS;
}

Esercizio 6: Modifica di più record usando MySQL C API (OOP)

Creare una classe per gestire la connessione a MySQL e modificare più record usando MySQL C API.

#include <mysql/mysql.h>
#include <iostream>
#include <stdexcept>

class MySQLClient {
private:
    MYSQL* conn;
public:
    MySQLClient(const std::string& host, const std::string& user, const std::string& pass, const std::string& db) {
        conn = mysql_init(nullptr);
        if (conn == nullptr) {
            throw std::runtime_error("mysql_init() failed");
        }
        if (mysql_real_connect(conn, host.c_str(), user.c_str(), pass.c_str(), db.c_str(), 0, nullptr, 0) == nullptr) {
            mysql_close(conn);
            throw std::runtime_error("mysql_real_connect() failed");
        }
    }

    ~MySQLClient() {
        mysql_close(conn);
    }

    void modificaRecords(const std::string& query) {
        if (mysql_query(conn, query.c_str())) {
            throw std::runtime_error("UPDATE failed: " + std::string(mysql_error(conn)));
        } else {
            std::cout << "Record modificati con successo." << std::endl;
        }
    }
};

int main() {
    try {
        MySQLClient client("localhost", "root", "password", "test_db");
        client.modificaRecords("UPDATE test_table SET status = 'inactive' WHERE status =

 'active'");
    } catch (const std::exception& e) {
        std::cerr << e.what() << std::endl;
    }
    return 0;
}