Hi David,
in a web-application you should ideally work with connection pooling, which is
usually done by the application server (i.e. Apache-Tomcat).
We recommend the following:
1. create an Application object which is instantiated and initialized once when
the web-application is loaded in the web application server. This can be done
via a custom filter class registered in the web.xml definition file of your
web-application. The application object is a singleton.
2. use a JNDI context to access a datasource provided by the application
server. When initializing your application obtain a Connection from the data
source and initialize your DB-Objects (create the driver, open the database,
check the schema, etc.)
3. for each request, obtain a connection from the pool which you can then pass
to the appropriate Empire-db function. When the request finished close the
connection which will effectively return it to the pool.
I recommend downloading and looking at our Empire-Struts2 Example Application
called DBWebSample provided with the distribution of the
empire-struts2-extentions. Even if you don't intend to use Struts2 as your web
application framework it gives a good idea on how to use Empire-db in a web
application. You should particularly look the init() method of the
SampleApplication class. However the sample application does not implement
connection pooling - but it can be easily added.
Hope this is the kind of answer you expected.
Regards
Rainer
David Marko wrote:
>
> Hello,
> can anyone share some common scenario on how to initialise necessary
> things in web application using
> e.g. SpringFramework?
>
> ##### Using the code from the EmpireDB Site:
> config.init((args.length > 0 ? args[0] : "config.xml"));
> // STEP 1: Get a JDBC Connection
> Connection conn = getJDBCConnection();
> In step two the sample creates and initializes a database driver object
> for the target DBMS. This is
> HSQLDB by default.
>
> // STEP 2: Choose a driver
> DBDatabaseDriver driver = getDatabaseDriver(config.getDatabaseProvider());
> Then in step three the database object is opened using the driver. Only
> when opened, other methods
> of the database object may be used. Finally we check whether or not our
> database objects exist.
>
> // STEP 3: Open Database and check if tables exist
> db.open(driver, conn);
> databaseExists(conn);
> In order to check existence of the database the sample simply performs a
> query on the Departments
> table ("select count(*) from DEPARTMENTS") using the following code:
>
> DBCommand cmd = db.createCommand();
> cmd.select(db.DEPARTMENTS.count());
> db.querySingleInt(cmd.getSelect(), -1, conn);
> ###
>
> ... should/can be the conn and db initialised using some singleton pattern
> and used within the
> application in this way?
>
> Thanks for info,
> David
