Re: Windows Ada database support.

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Mon, 29 Nov 2004 01:28:03 +0000 (UTC), Georg Bauhaus wrote:

> Dmitry A. Kazakov <mailbox@dmitry-kazakov.de> wrote:
>: And more importantly why that crappy SQL over and over again? I would like
>: to see a high level Ada.Database[.Relational?] package totally independent
>: on what happens beneath.
> 
> Because Ada is a high level systems programming language making
> you expect to be in control of well defined details?

Yes.

> What about COMMIT?

That's easy. There should be a transaction object, kind of "external"
protected object.

BTW, there is an interesting Ada problem associated with it. When I wrote
ODBC bindings I faced this problem:

declare -- Transaction in manual-commit mode
   Mutex : Write_Mutex (Connection'Access);
begin
   ...  -- Do some DB stuff
   Commit (Mutex); -- Nasty, but necessary
end;

Upon exception Write_Mutex.Finalize does roll-back. This in turn requires
that nasty call to Commit at the end of the scope. Commit just sets a flag
in Write_Mutex for Finalize. Because in Finalize there is no way to
determine whether the scope was left due to a stack roll-back upon an
exception. Probably it is worth an AI for Ada 2010.

> At what time should Oracle CURSORs be given up?

What about n-th level of CPU cache? Do you really care when you write an
Ada application? It is all compiler vendor business. As an application
developer, I want to hear nothing about cursors.

> How much precision can you portably specify for floating point
> values in your DB independent package?

The required precision should specify the application. And BTW, for a great
majority of applications that should rather be fixed point. So you can't
have any default.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de