Kamalika's Notebook

thinking nothing...............!!

PHP and MVC Design Pattern

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The root cause of writing Software is simple Software solves problems. We analyze the requirements and break them into smaller problems (modules) and then write the solution for each such problem. Every line of code (LOC) we write is meant to resolve some problem. A pattern or design pattern defines how we solve problems, we must remember that a pattern is never the solution itself it is a way solution is written or developed or rather architected.

Around the world developers and solution architects are always excited about using MVC in fact the developer community often frowns upon those who don’t use it! I remember one of friends who once asked me… “OMG! You are not using any MVC of framework? Just writing native code?”… I tried hard to reason… “We may not be using MVC but we are using patterns and its pure OOP, I don’t think such application really requires MVC!”… “No… No… I think you must!”… I resigned!

What exactly MVC has to offer:

  • Reduced Code complexity
  • Code reusability
  • Increased flexibility
  • Decoupled code

Have we ever thought? MVC cannot solve the Code complexity or reusability or even flexibility problem, it’s the developers who can solve these problems. Writing decoupled code is also a developer’s thing; a pattern like MVC will create and environment with certain restrictions and rules but the code has to be written by a developer, the logic behind the code has to be thought out by a human! [Read more…]

Write your first PHP program…

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Audience…

Audience of this article is any aspiring professional who is considering PHP programming as a career option.

Scope…

Scope of this article is limited to writing your first PHP program in XAMPP on Windows. I’m going to guide you to install and configure XAMPP on Windows and then write your first PHP script.

Topics…

–       Download, install and configure XAMPP on Windows

–       Write and run a PHP program / script

[Read more…]

Installing LAMP in Centos 6.3

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LAMP is the abbreviation of Linux, Apache, MySQL, PHP. In this article I’ll try to explain how you can install an Apache2 webserver on a CentOS 6.3 server with PHP5 support (mod_php) and MySQL support. This approach should work if you start from scratch, i.e., the server has only CentOS 6.3 installed and nobody ever tried to install or configure LAMP!

Caution! This article is meant for those who rarely have to work on such projects when no expert advice / support available!  By no means this should be used by any Linux Pro.

Introduction

While deploying Centos 6.3 onto the server please put hostname as localhost, and don’t bind the server to any particular IP address.

Architecting Scalable Systems for Cloud

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In my last post I asked whether “PHP is easy, is it a boon or bane?” because it is easy, most of the developers just develop systems but never pay attention to the architecture of the system on which they are developing. They never ask questions like “is the system stable?” or “will it be able to handle a lot of concurrent users?” or “is my code optimized enough for as the system required?” or “is the system that is holding my application and data designed well to ensure a better user experience?” or “is the system righteously architected / designed?”. Honestly I never asked myself a lot of these questions until I started working in Cloud Computing Environments, all that bothered me is the efficiency of my code, efficiency of my SQL queries, normalization status of my database, whether I need to de-normalize, finding solutions writing less numbers of lines of codes or single complex SQL JOIN queries, browser compatibility, etc, etc.

Encountering Cloud came as a shocker! I thought I knew fairly well about developing applications using LAMP stack, well I did know but what didn’t know was using LAMP stack on Cloud and what the architecture my cloud environment should have in order to sustain large volume of concurrent traffic. Also how should I write my SQL queries, how should I break a complex SQL query into multiple simple SQL queries and how should I complement complex database routines by PHP code. [Read more…]

Load Balanced Databases hosted in Cloud, MySQL ORDER BY and PHP Array Multi Sort!

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Load-Balanced-Databases-hosted-in-Cloud,-MySQL-ORDER-BY-and-PHP-Array-Multi-Sort!

If you have noticed there is an exclamatory sign (!) after the post title, let me tell you I have deliberately placed it to express my surprise on the whole thing which I’m going to share. I have been working with MySQL since early 2005, if I remember correctly it was version 4.1 which for the first time supported Sub Queries. I was a pure MySQL newbie back then and did not have any idea about how good or bad MySQL was. Honestly I switched from Microsoft Technologies to Open Source Technologies because my employer decided to switch to Open Source to avoid license costs, for obvious reasons I was skeptical about Free and Open Source MySQL and though very highly of MSSQL & MMC Console Microsoft offered! Since then till I faced the MySQL ORDER BY issue in Cloud I have used MySQL ORDER BY to solve all kinds of ranking problems, though I always knew MySQL sorting algorithm is not a great one, inside it uses qsort (quicksort) algorithm but if use the ORDER BY on a indexed field / key then it won’t cause much of an optimization issue. [Read more…]