| > 8.i currently does not support entity beans. We
| > completely believe that entity beans are not a solution
| > to light weight, fine grained persistence. We are going
| > to provide entity beans, as they are required, and they
| > are actually useful in certain cases.
| >
|
| The idea of using session beans talking directly to the
| database makes alot of sense as far as querying the system
| is concerned. What about transactional updates ? Are you
| and Javier talking about using session beans to directly
| update the system ? Does that result in a weak object
| model ? That may not be bad in the kind of non - trivial
| systems you're talking about - but I'm curious.
Using the Business Components for Java framework, querying
the system is performed using components called "View
Objects". These can use arbitrary SQL to get the view of the
data just right.
The API for working with a View Object looks just like a
RowSet. So you work with these optionally fully-scrollable,
optionally fully-updateable rowsets that have the full
power of SQL underneath (including arbitrary joins!)
Updates made through the View Objects coordinate with
appropriate Entity Objects where the business logic
lives. So what you get is a strong object model in your
associated and composed sets of Entity Objects, with a
strong query model using SQL.
| Do the session beans in such systems represent your
| presentation layer or the object model ?
The framework component called an Application Module
represents a component that is the logical datamodel you
want clients to see. This "datamodel" is a bag full of
(optionally master/detail coordinated) view objects that are
relevant to solve a paricular application task. Updates
through these views engage relevant business logic
automatically, and handle all database interaction
to post the changes.
________________________________________________________
Steve Muench, BC4J Development Team & XML Evangelist
http://technet.oracle.com/tech/java
http://technet.oracle.com/tech/xml
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