Re: Dreaming About Redesigning SQL

Carl Rosenberger wrote:

> Patrick K. O'Brien wrote:
>  
>
> > As I've said before, I haven't focused on optimization yet.  But I
> > remain convinced that an ODBMS with the proper object model can be
> > optimized as you describe.  Does that make me an optimist?  ;-)
> >    
>
> The proof is trivial:
>
> If you back up your object database system with a parallel fast
> relational system (or write that yourself), you should be able
> to achieve the same performance for relational queries as any
> relational database. :-)
>
>  
Right, but who is the guy that is going to write an optimiser for code 
like this:

def prod_cust_totals():
    """Return order summary information."""
    db = _database
    group = {}
    for od in db.root['OrderDetail']:
        key = (od.order.customer.name, od.product.name)
        subtotal = od.quantity * od.product.price
        group[key] = group.get(key, 0) + subtotal
    totals = [(t, c, p) for ((c, p), t) in group.items()]
    totals.sort()
    pprint.pprint(totals)

Granted, you can convert the refereces into simple SQL-queries
"under the cover" but how are you going to automatically transform this
code into, say, code that starts navigation from the customer table.
You will have to use some declarative approach instead so, in effect,
you are just writing "another SQL".  I understand that there are
some query languages (OQL?) available for object databases.  Are these
actually used in applications?  If not, why?

best regards,
Lauri Pietarinen