Declarative Transactions, Session Beans & JDBC

Question

Hi (this is really a newbie question),
If I executed an SQL Update statement in a Stateless Session Bean via JDBC,
is my call to the database enlisted in the container transaction
automatically? (Of course, I am assuming the correct TxRequired settings
are set on the deployment descriptors for the Session Bean.)
Asked in another way, how does JDBC "talk" to the EJB container to let it
know that it is being called within a Transactional Context and that all
activities with the database should then be enlisted in a transaction
automatically? Where does this "smartness" come in? Or does this not happen
at all - do I have to "obtain" the JDBC connection object from the EJB
container instead of writing directly to JDBC?
Thanks in advance,
Abdullah Kauchali

Answer 1

Correct.
I'd also recommend (where possible), doing the DataSource JNDI lookup in
your setSessionContext method and storing it away in a member variable.
There's usually no reason to do it on every method call.
-- Rob
Abdullah Kauchali wrote:
Okay,
After some investigations, this is what I've learned:
1. To get automatic transactional enlistment (in a distributed tx), you
have to make your EJB container aware of the JDBC datasource (viz. you have
to create a Transactional DataSource). This is done by creating necessary
entries in a configuration XML file so that the container can connect to the
JDBC datasource when fired-up;
2. You then only create your Connection object via a reference (JNDI to be
exact) to the connection object and NOT directly with JDBC (this was my
confusion in fact). Something like this:
//obtain the conduit to the JNDI resource manager factory
javax.sql.DataSource objDS = (javax.sql.DataSource)
context.lookup("~some jndi
reference~");
//now get the connection object - notice no "javax" but "java"
java.sql.Connection objCon = objDS.getConnection();
3. By doing 2. above you are actually using a "Resource Manager Connection
Factory" to get your Connection object for subsequent SQL Updates;
4. As long as your JDBC driver supports the javax.sql.DataSource interface
and provided Transactional Context is propagated from any root call to your
worker Session Bean, you get automatic transaction enlistment of the SQL
Updates with your EJB container;
Please correct me if I have concluded wrongly,
Regards
Abdullah
"Abdullah Kauchali" <ak@ak> wrote in message
news:[email protected]...
Hi (this is really a newbie question),
If I executed an SQL Update statement in a Stateless Session Bean viaJDBC,
is my call to the database enlisted in the container transaction
automatically? (Of course, I am assuming the correct TxRequired settings
are set on the deployment descriptors for the Session Bean.)
Asked in another way, how does JDBC "talk" to the EJB container to let it
know that it is being called within a Transactional Context and that all
activities with the database should then be enlisted in a transaction
automatically? Where does this "smartness" come in? Or does this nothappen
at all - do I have to "obtain" the JDBC connection object from the EJB
container instead of writing directly to JDBC?
Thanks in advance,
Abdullah Kauchali