DataBase db = new SQLServer();

// �f�[�^�x�[�X�ɐڑ����܂��B
db.Open();

// �f�[�^�x�[�X�ڑ����������܂��B
db.Close();

static void Main(string[] args)
{
    DataBase db = GetDataBaseInstance("MSAccess");
    
    // �f�[�^�x�[�X�ɐڑ����܂��B
    db.Open();

    // �f�[�^�x�[�X�ڑ����������܂��B
    db.Close();
}

private static DataBase GetDataBaseInstance(string dbName)
{
    DataBase db = null;
    switch (dbName)
    {
        case "MSAccess":
            db = new MSAccess();
            break;
        case "SQLServer":
            db = new SQLServer();
            break;
        case "Oracle":
            db = new Oracle();
            break;
        default:
            db = new SQLServer();
            break;
    }
    return db;
}

using System;
using System.Collections.Generic;
using System.Text;

namespace SimpleFactory
{
    public class SimpleFactory
    {
        public DataBase DataBaseFactory(string dbName)
        {
            switch (dbName)
            {
                case "MSAccess":
                    return new MSAccess();
                case "SQLServer":
                    return new SQLServer();
                case "Oracle":
                    return new Oracle();
            }
            return new SQLServer();
        }
    }
}

static void Main(string[] args)
{
    SimpleFactory factory = new SimpleFactory();
    DataBase db = factory.DataBaseFactory("Oracle");
    
    // �f�[�^�x�[�X�ɐڑ����܂��B
    db.Open();

    // �f�[�^�x�[�X�ڑ����������܂��B
    db.Close();
}