Re: Ada DB bindings and APQ

[Georg Bauhaus <sb463ba@l1-hrz.uni-duisburg.de>]

Dmitry A. Kazakov <mailbox@dmitry-kazakov.de> wrote:
: On Tue, 14 Dec 2004 02:25:22 -0500, Warren W. Gay VE3WWG wrote:
: Yep, the first error one gets: lpq not found. libpq.a is not distributed
: with GNAT. This might become a problem in the future.

I'm not at all surprised that when I use a binding but not the bound
thing, I'll get an error.

: Yes, but from user's perspective, at least one query per connection is
: always necessary. In some cases the user will need more, but not so often.

I doubt this very much. Indeed, we have a server type application
that does not work at all without a connection pool, because performance
is affected rather drastically when you control connections.
This is at least true for the DB systems we have had a chance to try.

If then you want one physical connection to play the part of a
"reusable" connection that is not in the way of programmers,
then why do you need one at all in the abstraction?
For example, how about ticket based query authentication?

: I do not see much sense in all that levels of types exposed to the user.

As a user, I agree that a DWIM DB abstraction is wonderful.
It just isn't practical when using current database technology :-)

: Internally of course. This could be necessary for "light-weight" connection
: cloning.
: 
: Handle --> Query_Object --> Connection_Object
: 
: 1. Handle copy (+1 reference count of Query_Object)
: 2. Light-weight copy: creates new query (+1 reference count of connection)
: 3. Heavy-weight copy: creates a new query and a new connection

This starts looking like optimazation techniques used in current
database systems.

: My case is much simpler. The application
: starts, it checks if DB exists, if not, it creates that empty.
: I believe,
: this is about 80% of needs for small applications.

Aha! So your goal is to have a convenient abstraction for
a specific kind of data storage in small applications?

: Anyway, there should be a uniform way of putting values into requests
: separated from SQL-keywords, and, probably, names of tables, of columns
: etc.

This again sounds like a newly designed Ada-interface based OO data storage
system for Ada programs... Go ahead :)


-- Georg