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Monday, August 25, 2008

Hibernate...

This video is a part of our continuous approach towards learning by sharing knowledge together. We deal with hibernate plugin onto the reverse engineering process we discussed earlier.

[googlevideo=http://video.google.com/videoplay?docid=7169964626981764870]

Sunday, August 24, 2008

AJAX

AJAX is simple.... It ought to be as you can even find books titled "Teach yourself AJAX in 10 minutes". I mean even the silliest of technology learning book titles have a minimum time span of 24 hours but by jove 10 minutes?? By the way the simplicity of ajax using jmaki plugin is demostrated in the following screencast(PS:don't feel bad, its a little screechy and 14 mins long but anyway gives an overview of jmaki and dojo). Now to the reality part, what exactly is AJAX? AJAX (asynchronous JavaScript and XML) isn'ta technology. It's really several technologies, each flourishing in its own right, coming together in powerful new ways. AJAX incorporates:

  • Standards based presentation using XHTML and CSS

  • Dynamic display and interaction using the document object model

  • Data interchange and manipulation using XML and XSLT

  • Asynchronous data retrieval using  XmlHttpRequest

  • and JavaScript binding everything together.


What is important to note is that it is easy to use ajax code from ajax libraries available  such as those from Yahoo, Google and DOJO to name a few, but to write your own code in AJAX its humongus. The only way to be good at AJAX is "Practice, practice and more practice".

Saturday, August 9, 2008

Reverse Engineering : An insight into the process of reverse engineering databases

Lets first look into the definition of reverse engineering. Reverse engineering (RE) is the process of discovering the technological principles of a device, object or system through analysis of its structure, function and operation. Reverse Engineering is a very powerful technique for discovering the structures of databases. There are many tools available like Apache Cayenee,Oracle Designer etc. What I want to talk thorough here is the concept of reverse engineering and its relevance into enterprise application development. You must be knowing that in the 3 tier system of Enterprise Applications other than the business code in the middle tier a lot of coding goes into both data access and modification in the innermost layer. So an enterprise app could be seen as a concentric sperical shell of three layers with the ineermost core dedicated to database(say db2),its connections and data access. Once we have this core, i.e. we know exactly what data is to be delt with we could use a tool to map the database directly to code(POJO and DAO combination in case of EJB's) and then build the rest of the application on top of this. This is reverse of the actual front end to back end conceptuation we tend to do and is termed reverse engineering. Its a relatively fast and effective method wherein the focus is exactly on the application data, enabling us to build on both existing databases and our own data logic on any given scenario.