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From: Knut Anders Hatlen <knut.hatlen@oracle.com>
To: "Derby Discussion" <derby-user@db.apache.org>
Subject: Re: metadata / getClientInfo()
References: <loom.20110723T122803-428@post.gmane.org>
	<x6livm8gzu.fsf@oracle.com> <loom.20110725T201024-926@post.gmane.org>
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Date: Mon, 25 Jul 2011 20:59:44 +0200
In-Reply-To: <loom.20110725T201024-926@post.gmane.org> (Thomas Hill's message
	of "Mon, 25 Jul 2011 18:25:24 +0000 (UTC)")
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Thomas Hill <Thomas.K.Hill@t-online.de> writes:

> okay - true. 
> I was however wondering and wanted to test whether I could replace a
> potentially in terms of performace more costly JDBC statement definition
> and result set processing of a 'select session_user from sysibm.sysdummy1'
>  by an assumed less costly request of a property from a connection object 
> I have  at hand anway?
> Even if this would turn out to not be better in terms of performance, I 
> think I would still like to understand how this getClientInfo() works. 
> When using SQuirreL I can see a lot of connection properties / metadata
> displayed under their 'metadata' tab that I would suspect they are getting
> via such mechanisms.
> In the derby docs I am afraid one hardly finds details on the subject.
> Thanks Thomas

In the lack of documentation, there's always the source... ;)

EmbedConnection40.java:

    /**
     * <code>getClientInfo</code> always returns a
     * <code>null String</code> since Derby doesn't support
     * ClientInfoProperties.
     *
     * @param name a <code>String</code> value
     * @return a <code>null String</code> value
     * @exception SQLException if the connection is closed.
     */
    public String getClientInfo(String name)
    throws SQLException{
        checkIfClosed();
        return null;
    }

So I'm afraid getClientInfo() won't be the solution to any of your
problems...

-- 
Knut Anders