Re: Simple database app with Forms/Flow ?

[Upayavira]

Derek Hohls wrote:
I am looking to try and build-up my learning on forms and flow (and
templating!) by applying this to a simple interactive database app.
In the past, I used XSP and ESQL, along with a primitive "meta forms"
XML file to generate a generic form *and* populate it with data,
followed
by  styling with XSLT. Database add/update/delete were then handled by
database actions in the sitemap (along with the corresponding table 
definition files).   This approach may seem  crude and simple but it
worked 
and bugs (if any) were usually in a single XSP file and easy to track
down.

I am now wondering what combination of "new" options to adopt in order
to replicate this approach in the simplest possible manner - I know
there has been lots of discussion on persistence frameworks; DTO's,
DAO's and business objects - but all this seems very much like over-
kill just to tackle a few tables with a few users (in other words, a
normal in-house, customised database app).  I have seen flow samples
with binding to beans and XML files, but nothing in terms of building
up
forms dynamically and then hooking then to a normal relational database
to read/write data.
 

I know that people keep harking back to O/R mapping. I've just done my 
first bit of hibernate, which I've always been mildly scared of ("isn't 
it overkill???"). I couldn't believe it was that easy. You create an 
object, and then persist it. Easy:

Here's the code to create a new User object:
           net.sf.hibernate.Session session = sessionFactory.openSession();
           Transaction transaction = session.beginTransaction();
           User user = new User();
           user.setEmail("[EMAIL PROTECTED]");
           user.setName("Upayavira");
           session.save(user);
           transaction.commit();
That is it. And then that user object and persist it. You can make an 
object like that, and bind it to a form. The object is yours, it is of 
your design.

Or to check whether a user exists or not with a simple query from a 
login form:

       try {
           transaction = session.beginTransaction();
           Query query = session.createQuery("from 
com.yoursite.formModels.User as user where user.email= :email and 
user.password=:password");
           query.setString("email", 
aForm.getChild("email").getValue().toString());
           query.setString("password", 
aForm.getChild("password").getValue().toString());
           result= (query.list().size()!=0);
           transaction.commit();
       } catch (Exception e){
           transaction.rollback();
           throw e;
       } finally {
           session.close();
       }
       return result;

That's how easy it is in Hibernate. Don't know about OJB. I've got a 
feeling I'll be using O/R mapping for all sites I work on now that have 
a relational DB involved, it seems that easy.

Hope I'm not banging a tired drum!
Regards, Upayavira


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