Запрос в бд MySQL на C++

#include <iostream>
#include <mysql.h>
#include <mysqld_error.h>
 
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
 
using namespace std;
 
int main() {    
    MYSQL* obj;
    MYSQL_RES* res;
    MYSQL_ROW row;
    
    if(!(obj = mysql_init(0)))
    {
        cout << " Error!";
    }
    
    if(!mysql_real_connect(obj, "localhost", "root", "Rjkby_VfrHtq1995", "testbase", 3306, NULL, 0))
    {
        cout << mysql_error(obj);
    }
    else 
    {
        cout << " Connect testbase succes!!!";
    }
    
    if(mysql_query(obj, "SELECT * FROM users;"))
    {
        cout << mysql_error(obj);
        return 1;
    }
    
        
    if (res = mysql_store_result(obj))
    {
        while(row = mysql_fetch_row(res))
        {
            for (int i=0 ; i <mysql_num_fields(res); i++)
            {
                std::cout<<row[i] <<"\n"; 
            }
        }
    } else cout << mysql_error(obj);
    
    if(mysql_query(obj, "INSERT INTO users VALUES ('vasya', '1530', '1500')") != 0)
  {    
    cout <<  "Error: can't execute INSERT-query\n";
    exit(1);
  }
 
    
    
    
    mysql_close(obj);
    
    system("pause");
    return 0;
}

string str;
cin >> str;
    if(mysql_query(obj, "INSERT INTO users(name) VALUES (str)") != 0)
  {    
    cout <<  "Error: can't execute INSERT-query\n";
    exit(1);
  }

#include <iostream>
#include <mysql.h>
#include <mysqld_error.h>
#include <string>
 
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
 
using namespace std;
 
int main() {
    
    MYSQL* obj;
    MYSQL_RES* res;
    MYSQL_ROW row;
    
    if(!(obj = mysql_init(0)))
    {
        cout << " Error!";
    }
    
    if(!mysql_real_connect(obj, "localhost", "root", "Rjkby_VfrHtq1995", "testbase", 3306, NULL, 0))
    {
        cout << mysql_error(obj);
    }
    else 
    {
        cout << " Connect testbase succes!!!";
    }   
    
    
    if(mysql_query(obj, "SELECT * FROM users;"))
    {
        cout << mysql_error(obj);
        return 1;
    }
    
        
    if (res = mysql_store_result(obj))
    {
        while(row = mysql_fetch_row(res))
        {
            for (int i=0 ; i <mysql_num_fields(res); i++)
            {
                std::cout<<row[i] <<"\n"; 
            }
        }
    } else cout << mysql_error(obj);
    
    string str1;
    cout << " str1: ";
    cin >> str1;    
    
    string str2 ;
    cout << " str2: ";
    cin >> str2;    
    
    string str3 ;
    cout << " str3: ";
    cin >> str3;    
    
    const char *stmt_str;
    string str4 ("INSERT INTO users(name, allattempts, successful) VALUES (" +  str1 +  str2   + str3 +  ")");
    stmt_str = str4.c_str();
    
    if(mysql_query(obj, stmt_str ) != 0)
  {    
    cout <<  "Error: can't execute INSERT-query\n";
    exit(1);
  }
    
    mysql_close(obj);
    
    system("pause");
    return 0;
}

#include <stdlib.h>
#include <iostream>
 
/*
Include directly the different
headers from cppconn/ and mysql_driver.h + mysql_util.h
(and mysql_connection.h). This will reduce your build time!
*/
#include "mysql_connection.h"
 
#include <cppconn/driver.h>
#include <cppconn/exception.h>
#include <cppconn/resultset.h>
#include <cppconn/statement.h>
#include <cppconn/prepared_statement.h>
 
using namespace std;
 
int main(void)
{
    cout << endl;
    cout << "Let's have MySQL count from 10 to 1..." << endl;
 
    try {
        sql::Driver *driver;
        sql::Connection *con;
        sql::Statement *stmt;
        sql::ResultSet *res;
        sql::PreparedStatement *pstmt;
 
        /* Create a connection */
        driver = get_driver_instance();
        con = driver->connect("tcp://127.0.0.1:3306", "root", "Rjkby_VfrHtq1995");
        /* Connect to the MySQL test database */
        con->setSchema("testbase");
 
        stmt = con->createStatement();
        stmt->execute("DROP TABLE IF EXISTS test");
        stmt->execute("CREATE TABLE test(id INT)");
        delete stmt;
 
        /* '?' is the supported placeholder syntax */
        pstmt = con->prepareStatement("INSERT INTO test(id) VALUES (?)");
        for (int i = 1; i <= 10; i++) {
            pstmt->setInt(1, i);
            pstmt->executeUpdate();
        }
        delete pstmt;
 
        /* Select in ascending order */
        pstmt = con->prepareStatement("SELECT id FROM test ORDER BY id ASC");
        res = pstmt->executeQuery();
 
        /* Fetch in reverse = descending order! */
        res->afterLast();
        while (res->previous())
            cout << "\t... MySQL counts: " << res->getInt("id") << endl;
        delete res;
 
        delete pstmt;
        delete con;
 
    }
    catch (sql::SQLException &e) {
        cout << "# ERR: SQLException in " << __FILE__;
        cout << "(" << __FUNCTION__ << ") on line " 
            << __LINE__ << endl;
        cout << "# ERR: " << e.what();
        cout << " (MySQL error code: " << e.getErrorCode();
        cout << ", SQLState: " << e.getSQLState() << 
            " )" << endl;
    }
 
    cout << endl;
 
    return EXIT_SUCCESS;
}