Suitable EJB for operations on two tables

Question

Hi All,
I would like to create a stateless session bean that removes a record from one table and inserts into another table. The method I will be using must be transactional integrity giving me "all or nothing proposition". How can I make sure the failure of the second database operation automatically results in the rollback of the first one.
Thank you.

Answer 1

Greetings,
Hi All,
I would like to create a stateless session bean that
removes a record from one table and inserts into
another table. The method I will be using must be
transactional integrity giving me "all or nothing
proposition". How can I make sure the failure of the
second database operation automatically results in the
rollback of the first one.The distributed transaction management of EJBs will take of this for you on the database side of things. What remains is that you code your bean appropriately for the transaction management model (BMT or CMT) of your bean...
First, remember that a Stateless SB cannot carry transaction contexts across multiple client->bean method calls, so your resource operations must occur within the same client method call:
* CMT *
...updateTables()
    try {
        /* Perform database operations... */
    catch( SQLException sqle ) {
        try {
            context.setRollbackOnly();  // Tell Trans. Mgr. operation failed
        catch( IllegalStateException ise ) {
            throw new EJBException( "Deployment error!" );
}* BMT *
...updateTables()
UserTransaction ut = null;
try {
ut = context.getUserTransaction();
catch( IllegalStateException ise ) {
throw new EJBException( "Deployment error!" );
try {
ut.begin();
/* Perform database operations... */
ut.commit();
catch( SQLException sqle ) {
try {
ut.rollback();
catch( IllegalStateException ise ) {
throw new EJBException( "Deployment error!" );
catch( <Exception+> e ) { ... }
The last <Exception+> in the above code can be one of:
* NotSupportedException - a consequence of calling ut.begin() and a transaction is already in effect
* RollbackException - if the transaction cannot be commited (another participant called a ROLLBACK)
* IllegalStateException - if a transaction is not in effect when ut.commit() is called
Note: All transaction method calls may also throw a SystemException in case of (um, well...), system errors.
In EJB 2.0 you can also get a HeuristicMixedException from ut.commit() if the trans. mgr. decided a ROLLBACK was necessary.
I hope this helps.
Thank you.Regards,
Tony "Vee Schade" Cook