Design Patterns

Design patterns provide efficient and standardize solutions for the software problems that occurs again and again. This design patterns can be use to develop high quality robust applications. But the thing is you have to select the right design pattern for the right problem. Once the selected pattern is need to change lot from its initial pattern too much, that means selected pattern is not adopted to your need. And picking the wrong pattern will lead you to write inefficient, complex and unmanageable code.

You can also create your own custom design patterns. Whenever you come up with a solution that can be re use in your application you may create a abstract pattern of it and re use in your application.

In this article I am going to discuss the famous design patterns introduced by the Gang of Four(GoF) using c# Code. Those patterns can be apply for any language.

We can group those design patterns into three groups.

• Creational Design Patterns 
• Structural Design Patterns
• Behavioral Design Patterns

cont.... 

Sql Dependency

In a recent project I wanted to share data between different instance. I tried different things like getting data using a timer and reading throug a web service. It had some slowness and I research about this and found about the "Sql Dependency.

Sql dependency was introduced in sql 2005 to provide data flow between separate instances of an application. This is a query notification feature of the sql. This query notification feature lets to subscribe for a query such that when the result of that query changes it will notify to the subscriber. This notification is a message.

Sql Dependency is a special .Net Class which is under the System.Data. This allows you to subscribe for a event and later subscribe command get the notification from the sql server. This notification triggers for each and every insert and deletes and send the notification to the subscriber. So we can get the table changes instantly using this feature. This has some effect on the inser and update commands. But this is very handy and you don't need to poll the database every now and then to get updates.

Following link is one of the best links that I have found. It demonstrate all the little things related to this topic.

http://www.codeproject.com/Articles/144344/Query-Notification-using-SqlDependency-and-SqlCach

Definition of: Oracle database

A relational database management system (DBMS) from Oracle, which runs on more than 80 platforms. Oracle was the first database product to run on a variety of platforms from micro to mainframe and were introduced in the late 1970s.

The Oracle database is Oracle's flagship product, and version 11g was introduced in 2007.

The Oracle "i" and "g" Versions

Starting in 1999 with Version 8i, Oracle added the "i" to the version name to reflect support for the Internet with its built-in Java Virtual Machine (JVM). Oracle 9i added more support for XML in 2001. In 2003, Oracle 10g was introduced with emphasis on the "g" for grid computing, which enables clusters of low-cost, industry standard servers to be treated as a single unit.

.NET ARCHITECTURE

.NET Framework

Runtime environment, Classes, API’s, Tools needed to build and deploy ".NET Applications".

The .NET Framework is required to build and run any .NET application and is available today as a download via Windows Update or directly from the Microsoft .NET Web site
(http://www.microsoft.com/net).

A major and important component of .NET Framework is the runtime environment (understands the instruction and execute them).

What is CLR

A .NET Application is compiled into IL (Intermediate Language), Also known as MSIL (Microsoft Intermediate Language) or Managed Code.

The runtime environment in .NET is called CLR (Common Language Runtime).

CLR Compile IL code and executes it.

.NET Languages

• Multiple languages (syntaxes) are supported in .NET Framework to build .NET Applications.

• E.g. C#, Visual Basic.NET, J#, Managed C++.

What is Java

Java

Java An object-oriented programming language that is platform independent (the same Java program runs on all hardware platforms without modification). Developed by Sun, Java is widely used on the Web for both client and server processing. Modeled after C++, Java added programming enhancements such as "garbage collection," which automatically frees unused memory. It was also designed to run in small amounts of memory. The first Web browsers to run Java were Sun's HotJava and Netscape Navigator 2.0.

Applets, Applications and Servlets

Java programs can be called from Web pages or run stand alone. When launched from a Web page, the program is called a Java "applet." When a non Web-based Java program is run on a user's machine, it is a Java "application." When running in a Web server, it is a Java "servlet."

Intermediate Bytecode

The source code of a Java program is compiled into an intermediate language called "bytecode," which can reside on any hardware platform. In order to run the bytecode, it must be compiled into machine code either ahead of time like a C/C++ program, just before it is needed or via a Java Virtual Machine (JVM), which is a line-at-a-time interpreter. There are compilers and JVMs for all major hardware platforms, and the intermediate bytecode is what makes Java machine independent.

What is .Net

.NET is both a business strategy from Microsoft and its collection of programming support for what are known as Web services, the ability to use the Web rather than your own computer for various services. Microsoft's goal is to provide individual and business users with a seamlessly interoperable and Web-enabled interface for applications and computing devices and to make computing activities increasingly Web browser-oriented. The .NET platform includes servers; building-block services, such as Web-based data storage; and device software. It also includes Passport, Microsoft's fill-in-the-form-only-once identity verification service.

The .NET platform was designed to provide:

• The ability to make the entire range of computing devices work together and to have user information automatically updated and synchronized on all of them

• Increased interactive capability for Web sites, enabled by greater use of XML (Extensible Markup Language) rather than HTML

• A premium online subscription service, that will feature customized access and delivery of products and services to the user from a central starting point for the management of various applications, such as e-mail, for example, or software, such as Office .NET

• Centralized data storage, which will increase efficiency and ease of access to information, as well as synchronization of information among users and devices
  The ability to integrate various communications media, such as e-mail, faxes, and telephones

• For developers, the ability to create reusable modules, which should increase productivity and reduce the number of programming errors

Microsoft expects that .NET will have as significant an effect on the computing world as the introduction of Windows. One concern being voiced is that although .NET's services will be accessible through any browser, they are likely to function more fully on products designed to work with .NET code.