using System;
using System.Collections.Generic;
using System.Data.Odbc;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ODBCTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string queryString = "SELECT * FROM SQLUser.ACCOUNTS";
            var command = new OdbcCommand(queryString);

            string connectionString = "DRIVER={InterSystems ODBC};SERVER=localhost;PORT=1972;DATABASE=USER;UID=_system;PWD=SYS;";
            using (var connection = new OdbcConnection(connectionString))
            {
                command.Connection = connection;
                connection.Open();
                var result = command.ExecuteReader();
            }
        }
    }
}

using (var connection = new OdbcConnection("DRIVER={InterSystems ODBC35};SERVER=localhost;PORT=1972;DATABASE=SAMPLES;UID=_system;PWD=SYS;Unicode SQLTypes=1;"))
{
  using (var command = new OdbcCommand("SELECT top 3 * FROM Sample.Person", connection))
  {
    connection.Open();
    var result = command.ExecuteReader();
    while (result.Read())
    {
      //textBox1.Text += result["SSN"] + Environment.NewLine;
      Console.WriteLine(result["SSN"]);
    };
  }
}

#include <QCoreApplication>
#include <QtCore>
#include <QtSql>
#include "iostream"

int main(int argc, char *argv[])
{
    QSqlDatabase db = QSqlDatabase::addDatabase("QODBC");
    db.setDatabaseName("DRIVER={InterSystems ODBC};SERVER=localhost;PORT=1972;DATABASE=USER;UID=_system;PWD=SYS; Unicode SQLTypes=1;");

    if (!db.open())
    {
        std::cout << "Error opening database" << std::endl;
        return -1;
    }
    else
    {
        QSqlQuery query;
        if(query.exec("SELECT * FROM ACCOUNTS")){
            std::cout << "Select succses!" << std::endl;
        }

        while (query.next())
        {
            std::cout << "Getting results..." << std::endl;
            std::cout << query.value(0).toString().toStdString() << std::endl;
        }

        std::cout << "EXIT!" << std::endl;
        return 0;
    }
}

std::cout << query.lastError().text().toStdString();

CacheODBC.dll
CacheODBC64.dll
CacheODBC35.dll -- соответственно этот
CacheODBC3564.dll