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Re: InstantDB: What's involved in getting prepared statement meta data working


Hi George

>> What's involved in supporting meta data from
>> prepared
>> statements?

I think the answer is "not a lot". I don't really know why it was never
implemented. I'll make sure it gets into the next beta (too late for beta 2
unfortunately). Then again, I'm not sure what it's advantage is over
ResultSet.getMetaData(), which you could presumably use as a work around
until the PreparedStatement call gets implemented.

>My guess is that InstantDB doesn't precompile
>statements, just assembles a string statement from the
>supplied arguments.

It goes half way there. It only parses prepared statements once. Then,
during the first execution, it caches statement elements so that they don't
have to be searched during subsequent executions. There is normally quite a
bit of benefit to be gained from using PreparedStatements in InstantDB.

Regards

Peter Hearty
Lutris Technologies UK Ltd.
-----Original Message-----
From: george stewart <georgestewartiv@yahoo.com>
To: instantDB@enhydra.org <instantDB@enhydra.org>
Date: 17 August 2000 01:48
Subject: Re: InstantDB: What's involved in getting prepared statement meta
data working


>
>--- george stewart <georgestewartiv@yahoo.com> wrote:
>> To InstantDB maintainers,
>>
>
>>
>> I'll experiment with this, but ask anyway.  How will
>> InstantDB behave if setObject(xx, null)?  Does it
>> set
>> to null, or do I need setNull(xx, type).
>>
>
>I exercised this and setObject(xx, null) behaves
>nicely.  It sets the column value to 'NULL'.  Both on
>insert and update.
>
>My guess is that InstantDB doesn't precompile
>statements, just assembles a string statement from the
>supplied arguments.
>
>Now, if there was just some way to determine if the
>JDBC driver supported metadata from prepared
>statements.  Currently, the only option is to try and
>then catch the exception.
>
>Regards, george
>
>
>__________________________________________________
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