Mailing-List: contact derby-user-help@db.apache.org; run by ezmlm
Precedence: bulk
Reply-To: "Derby Discussion" <derby-user@db.apache.org>
Received-SPF: pass (athena.apache.org: local policy)
Message-ID: <48A17D30.3080808@informatik.uni-kl.de>
Date: Tue, 12 Aug 2008 14:08:16 +0200
From: Boris Stumm <stumm@informatik.uni-kl.de>
User-Agent: Thunderbird 2.0.0.16 (X11/20080707)
MIME-Version: 1.0
To: Derby Discussion <derby-user@db.apache.org>
Subject: Re: Invoking methods directly in query
References: <489B1EB9.8040105@informatik.uni-kl.de> <489B4228.8060901@sun.com>
In-Reply-To: <489B4228.8060901@sun.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit

Hello Rick,

Rick Hillegas wrote:
[...]
> Unfortunately, the syntax used to declare those object types was not the 
> SQL Standard syntax for declaring abstract data types. Before Derby was 
> open-sourced, that non-standard syntax was removed so that Derby could 
> conform closely to the SQL Standard--that is an important part of 
> Derby's charter. The system tables and metadata queries were not 
> changed, however. Internally, Derby can still store objects in columns 
> and execute methods off those columns in queries.

I see... and found some points in the code to change, but I think
I first try out your advice on doing it.

[...]
> (2) You can write your own functions to unpack the information in the 
> TypeDescriptor that is stored in the columndatatype column. In a moment, 
> I will show you how to do this. Please bear in mind that TypeDescriptor 
> is not part of Derby's public API and that the following code is not 
> guaranteed to work in future releases of Derby. On the positive side, 
> TypeDescriptor has tended to evolve in upward compatible ways.
> 
> Here is a function which extracts the type name out of a TypeDescriptor:
[...]

Thank you very much for this help, it will save me a lot of time :-)
I hoped to avoid opening a new connection and use a new query because
of performance reasons, but I guess I just give it a try and see if
it is really that bad.

[...]
> Hope this helps,

Yes, it did! Thanks a lot,
Boris

-- 
Dipl.-Inf. Boris Stumm; Department of Computer Science, University of
Kaiserslautern; P.O. Box 3049, 67653 Kaiserslautern, Germany
Tel.: +49 631 205 3264, Fax: -3299
http://lgis.informatik.uni-kl.de/cms/index.php?id=41