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From Boris Stumm <st...@informatik.uni-kl.de>
Subject Re: Invoking methods directly in query
Date Tue, 12 Aug 2008 12:08:16 GMT
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,

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

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