Friday, 9 January 2009

Structured process you must know to develop a web application

Developing a web application is a hard work which requires much time you have to spend doing a myriad of things. If you don't use a methodic approach, especially in case of a complex project, you run the risk of losing sight of the project, not respecting times of delivery and wast your time for nothing.

This post illustrates a structured process which helps you to simplify the approach to develop your web applications saving time and more efficiently.

Download The Woork Papers N1 | Structured process you must know to develop a web application

Process main phases
In a generic web application developing process you can identify five main phases:

1. Requirements definition
2. Design
3. Implementation
4. Test
5. Release

Planning and Monitoring is a "cross phase" which follows developing process defining a project plan composed from a list of activities which you have to monitor during project execution. For each activity you have to define a set of information useful for its monitoring, for example:

- owner
- duration
- costs
- ...

Take a look at these posts I wrote some time ago about how to implement a project plan with a Gantt chart using Excel or Google Spreadsheets:

How to organize a project plan
Excel Gantt chart template
Implement a project plan and manage activities with Google Spreadsheets


1. Requirements Definition
In this first phase you have to define the scope and needs of your web application in terms of what your application must do, main features and technical requirements:



Scope
In order to define the scope of your web application is sufficient to compile a detailed list with a clear description of application features. At the moment is not important "how" you'll realize them but "what" you have to realize!

Needs
Needs analysis is a crucial part of developing process. In this step you have to estimate your potential traffic, choose a server-side language (PHP, ASP, Coldfusion...), database, choose an hosting service... Place a big attention on not to overrate/underrate your estimates! Evaluate every thing with a right balance between times, costs and objectives!


2. Design
After requirements definition phase, you have to "design" your application with a clear project. In this phase you can identify the following steps:




Design: Application Map
An application map contains just meaningful and essential information about the structure of your application: pages (represented with some blocks) and main relationships between them. Your application map could be something like this:


In this way you have a map with some "locations" (pages) and a "path" (relationships between pages) which you simply have to follow in order to proceed, page-by-page, to implement your application in the next phase. In this way you'll save a lot of time, having clear in mind what you have to implement.


Design: Database
Ok, now it's time to design application database. A simple way to do that it's using a entities-relationships (ER) model. In general you can follow this order: define first tables, than attributes and relationships between tables. Your ER model will be like this:



1:1 expresses the cardinality of a relationship (in this case for example 1 user is assigned only to 1 task, 1 user live only in a city). For more information about this topic take a look at my old posts:

Define the entities-relationships model
A correct approach to define relationships between database tables
10 Useful articles about Database design


Design: Page Structure
Next step is to design an approximate structure of the page, identifying all main sections using a name (for example #header, #navbar, #mainContent, #sidebar).

Design: Server-side Language
Taking a mind an object-oriented approach for developing your application, you can defining classes, functions and all server-side features you need. Remember... that's not the "implementation" but a way to have a "guide" for that you'll implement in the next phase.

Design: JS Framework
In this step choose a JavaScript Framework (jQuery, Scriptaculous, MooTools...), than pass to identify the main features you want to implement (drag and drop, animation effects...) compiling a simple list which associates each specific feature to one or more pages identified in you application map.

A this point design phase is completed. Let's start with implementation!

3. Implementation
Ok.. now starts the real challenge because "implementation" is the realization of your application. You can divide this phase in the following steps:



Implementation: Database
Create a new database and write SQL code defining tables, attributes and relationships. In the past I dedicated some posts about this topic. Take a look at the following links for more information:

How to use PHP and SQL to create DB tables and relationships
Create tables and relationships with SQL

Implementation: HTML
Use the page structure you defined in Design phase to implement HTML code:

<div id="header"> </div>
<div id="navbar"> </div>
<div id="mainContent"> </div>
<div id="sidebar"> </div>
<div id="footer"> </div>

This is the moment to add all HTML elements you need in sections identified during Design phase. For example if the sections mainContent contains a post with a title, a text body and post tags, add these elements:

<div id="header"> </div>
<div id="navbar"> </div>

<div id="mainContent">
<h1><!-- Post title --></h1>
<p><!-- Text body --></p>
<small><!-- Post tags --></small>
</div>


<div id="sidebar"> </div>
<div id="footer"> </div>

Implementation: CSS
When the main structure is ready, start to write CSS code to add styles to your application. If you need some suggestions about how to write a better CSS code take a look at these posts:

CSS coding: semantic approach in naming convention
Useful guidelines to improve CSS coding and maintainability

Implementation: Server-side language
Implement application class, application functions, DB interactions, queries, and every thing requires a server-side interaction.

Implementation: JavaScript
Implement Ajax features
(drag and drop, animation effects...) using the framework you chose in Design phase (jQuery, Scriptaculous, MooTools...).


4. Test
During this phase you have to "stress" your application executing your code in various conditions (for example using different browser). Your objective is to detect all application bugs and fix them before the final release.



Remember, this process must be methodic and require a lot of patience! Test each page and each features (also in this case can help you application map to proceed in a certain order). If you find a bug during test esecution, fix it modifying the code and than proceed with the final validation (an ulterior test) of the code.

5. Release
Finally you are ready to release your application! Publish it in a test folder and make a final test. If it's all ok proceed to the final release.

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Download The Woork Papers N1 | Structured process you must know to develop a web application



That's all. I hope this post can halp all of you which asked to me to add a post about this topic.
If you have suggestions to improve this process add a comment! Thanks :)

Related posts
- Structured process you must know to develop a web application
- Simple process to estimate times and costs in a web project
- How to manage a small web project: a simple approach
- Simple process to estimate times and costs in a web project
- The Deming Cycle: an application to web design

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