internal class MSSQLService : IDisposable
    {
        private const string SQL_USER = "";
        private const string SQL_PASSWORD = "";

        private SqlConnection _connection;

        public MSSQLService(string server, string databaseName)
        {
            SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder();
            builder.ApplicationName = "DataExchange.DocDoc";
            builder.ConnectTimeout = 30;
            builder.DataSource = server;
            builder.InitialCatalog = databaseName;
            builder.UserID = SQL_USER;
            builder.Password = SQL_PASSWORD;
            builder.PersistSecurityInfo = true;
            _connection = new SqlConnection(builder.ConnectionString);
        }

        public void UpdateCouponsStatus(IEnumerable<Coupon> coupons)
        {
            <...>
        }

        public bool IsNeedSync(out DateTime lastSyncDate)
        {
            <...>
        }

        public void RegistryError(string errorMessage)
        {
            <...>
        }

        public void Dispose()
        {
            if (_connection != null)
            {
                _connection.Dispose();
                _connection = null;
            }
        }
    }