I read somewhere that in MySQL the default storage engine is MyISAM. I heard that MyISAM does not support transactions. However, when I used my servlet that had the code for Transactions in the Quickstart like:
try {
Session session = HibernateUtil.currentSession();

Transaction tx= session.beginTransaction();

Cat princess = new Cat();
princess.setName("Princess");
princess.setSex('F');
princess.setWeight(7.4f);

session.save(princess);
tx.commit();

HibernateUtil.closeSession();

}

So was this a fluke my servlet worked, like I might have done something I did not know I did to make it work? If so, do I need code in my servlet to specify like that I should use the InnoDB storage engine? To change storage engines is all I need to do is to put ALTER Table in my mysql command lines, and I don't have to use any java code in my servlet right? I would appreciate help also in saying how I would go about changing the storage engine.

Thank you,
Kenneth Louie

At least I think MySQL 4.0.2d uses MyISAM as the default. Please correct me if I'm wrong. My above question still applies though and I would appreciate an answer very much.

Thank you,
Kenneth Louie

I am a beginner.

could you tell me the difference among the storage engines of MYSQL.

Thanks
,hehe

Not sure myself. I think like different storage engines store different things. So would use different amounts of memory. Like storage engines are like table types. I am a beginner too, heh and all I read was that MyISAM doesn't do transactions but InnoDB does. I was wondering if the default was MyISAM and it doesn't support transactions, then why did my code work? Maybe the default isn't MyISAM? And also how would I change the storage engine to InnoDB, and if this involved just MySQL or do I have to modify my servlet or the xml files.

Thank you,
Kenneth Louie

You can still do transaction demarcation, it just won't have any effect when using MyISAM tables. Try to do a rollback for example and you'll see.

So to change my table to InnoDB instead of MyISAM all it takes is MySQL code right? So when I create my table in MySQL I just need to specify what storage engnine I want right? I don't need to specify anything special in my servlet code or my server.xml or hibernate.cfg.xml or cat.hbm.xml to use the InnoDB storage engine right? I would appreciate any help.

Thank you,
Kenneth Louie

No.

P.S. If you need this kind of handholding, consider reading Hibernate in Action.