We are trying to migrate our data from MySQL ISAM to InnoDb to get transaction support. How does Hibernate identify the type of servlet engine. Would it be sufficient to use the MySQLDialect or do we have a subset based on the type of engine.

Thanks in advance.

I use a mix of MyISAM and InnoDB. I didn't have to use the separate dialects.

From previous experience with MyISAM, I recall that an exception is raised when we try to do something along the lines of session.connection().setAutocommit(false); because the underlying databse does not support transactions. But this should not be happening with InnoDb. Does this mean that the developer will need to handle any issues that arise when we use a combination of the two or will hibernate handle this transparently. I noticed that hibernate3 supports separate dialects for the two.

The best I can tell you is that I use it within EJB 3.0 entity beans called from session beans. The default transaction for session beans is 'requires'.

I am not certain what is going on behind the scenes. But, it just works.

Thats a novel approach to transaction processing :)

...you mean...it just works... that's the goal, right?

:)

Thanks for this.

We intend to keep it simple for now and not use entity beans. We do plan to use the Spring framework though to handle transactions and opening and closing of sessions. I assume then it would be safe to have a combination of both storage engines in a single logical database and use the MYSQLDialect alone.