Proxy Design Patterns in C#

A proxy is an object that can be used to control creation and access of a more complex object thereby deferring the cost of 
creating it until the time its needed.

class Program
    {
        static void Main(string[] args)
        {
            JournalProxy proxy = new JournalProxy();
            string s="teststring";
            proxy.GetSearchResults(s);
            proxy.InsertNewRow(System.DateTime.Now);
        }
    }

    public interface IJournalData
    {
        void InsertNewRow(DateTime dateTime);
        DataTable GetSearchResults(string queryString);
    }

    //Database layer
    class JournalLayer : IJournalData
    {
        public void InsertNewRow(DateTime dateTime)
        {
            return;
        }

        public DataTable GetSearchResults(string queryString)
        {
            return new DataTable();
        }
    }

    //Proxy
    public class JournalProxy : IJournalData
    {
        JournalLayer _journalLayer;
        string _password;

        public bool Authenticate(string suppliedPassword)
        {
            // User sends in the password, and we make sure it is correct.
            if (string.IsNullOrEmpty(suppliedPassword) || suppliedPassword != _password)
            {
                return false;
            }

            // Password is correct. Allocate the database layer, and
            // setup the connection to the database code.
            _journalLayer = new JournalLayer();
            return true;
        }

        public void InsertNewRow(DateTime dateTime)
        {
            // In every method that the proxy implements from the interface,
            // make sure that the user was authenticated.
            if (_journalLayer == null)
            {
                return;
            }
            // Forward the call to the actual database code.
            _journalLayer.InsertNewRow(dateTime);
        }

        public DataTable GetSearchResults(string queryString)
        {
            if (_journalLayer == null)
            {
                return null;
            }
            return _journalLayer.GetSearchResults(queryString);
        }
    }