Subject Re: [IBO] IBO/IB_Query PrepareSQL question - does it fire on form creation? can I avoid that?
Author Helen Borrie
At 12:08 AM 4/10/2005 +0200, you wrote:
>I'm just playing around with the onprepareSQL events of IBOquery and
>Am I right, that both are firing during the form create event (which is also
>establishing the above query components)?

Yes, if you make the datasets active during FormCreate. This isn't good
client/server practice anyway, and is a relic of the BDE and Paradox.

>Is there a safe way to prevent this preparation?

Yes. Don't open datasets until you are ready to have them open. The Open
call (or setting a dataset to Active, which is another nasty relic from
Paradox) requires the statement to be prepared. So, if you tell your app
to open a dataset, it will automatically test for Prepared and, if it's not
prepared, it will call Prepare.

>I'd like to set some
>sqlwhereitem modficitations, which are not available on form creation time,
>but later before the form shows up.
>To speed up things, the first automated prepare is useless and I'd like to
>avoid it. The prepare should happen on the query actication or can be done
>manually by my program in formshow.

Follow the recommended order for opening your datasets.

For OnPrepareSQL to work, the dataset must be in the unprepared
state. Modifying SQLWhereItems and/or SQLOrder of course changes the
specification of the dataset so the Unprepare should occur automatically
when you call SQLWhereItems.Clear or SQLOrder.Clear. For DML statements,
it's wise to be a little more particular, and test for Prepared yourself.

if MyStatement.Prepared then MyStatement.Unprepare;