Work with Local SQL database using AIR

BANGALORE, INDIA: One good feature in Adobe's AIR, the platform for developing rich Internet apps is a database engine that runs within AIR's runtime environment. Since all the database files are stored locally, there is no need of an external database connection.

This also implies that persistent application data can be stored conveniently on the local drive. The local database is stored as a single file in the computer's file system. The runtime is responsible for creation, retrieval and manipulation of data in this database file. In the following implementation, we will be using synchronous mode of execution to create RIAs with AIR.

Implementation
Let's start with installation of AIR SDK. This can be downloaded from 'www.adobe.com or you can also get it from this issue's DVD. Once extracted to a folder, set the PATH environment variable. This can be done by adding reference of extracted folder to it. In our case, we added the following path in the end of PATH environment variable 'C:\AdobeAIRSDK\bin'.

The bin folder present in SDK contains ADL and ADT tools. AIR debug launcher or ADL is used to run applications without packaging them, whereas AIR developer tool is for packaging your application as an AIR file for distribution. One more important file that we would be using in this implementation is 'AIRaliases.js' present in 'C:\AdobeAIRSDK \frameworks\libs\air' folder.

This file provides alias definition that allows one to run 'ActionScript' runtime class i.e. air.FileStream, air.SQLDatabase etc. To use this file, one needs to add following script reference in HTML page:

Start with creating a folder that contains three files: XML file (pcquest.xml), HTML file (pcquest.html) and AIRaliases.js file as explained above. We will start with the applications descriptor file (pcquest.xml). Here is the content of this file along with explanation:

Next line shows attribute to uniquely identify application:

sandeep.com

One can also define version of the application as :

version 1.0
sample
AIR Example

To define properties of the application window:

pcquest.html

To check the results of the created application, open command prompt and move to the application folder and type in the window:

Adl pcquest.xml

Finally one can easily package AIR application in just two steps, start with creating certificate and key pair for application as shown here:

adt -certificate -cn SelfSigned 1024-RSA testCert.pfx password

To create .air installer file, simply run following command, it will prompt for password :

adt -package -storetype pkcs12 -keystore testCert.pfx PCQUest.air pcquest.xml pcquest.html

Now one can distribute this application using PCQUest.air file. This shows how web developers having SQL knowledge can use their SQL skills in easily developing applications in AIR.

Now we have created the required descriptive file. Let's create a HTML page that contains code to create database and then display that database. Here is the code snippet showing the content of 'pcquest.html':