Re: SQL with parameters - need to PREPARE and 'OPEN ... USING'?

I can kind of see that...maybe :)

ODP shouldn't be job specific. And the DBMS should be able to tell which
table is actually supposed to be open. Same thing goes for the SQL plan
cache and the access plan information stored in the programs/service
programs.

In fact, the IBM documentation says

In all the preceding cases where a plan is saved, including static SQL,
dynamic replan can still apply as the queries are run over time.

The access plan is validated when the query is opened. Validation includes
the following:

- Verifying that the same tables are referenced in the query as in the
access plan. For example, the tables were not deleted and recreated or that
the tables resolved by using *LIBL have not changed.


https://www.ibm.com/support/knowledgecenter/ssw_ibm_i_72/rzajq/apvalid.htm?lang=en

I assume you had a PMR open? The answer they came back with was to use
dynamic SQL?

If it where my PMR, I think I'd push back on that a bit.

Charles

On Wed, May 11, 2016 at 1:09 PM, <dlclark@xxxxxxxxxxxxxxxx> wrote:

"RPG400-L" <rpg400-l-bounces@xxxxxxxxxxxx> wrote on 05/11/2016 12:56:44
PM:

There's really only a single instance where you need really dynamic SQL,
that's when the affected table isn't known till run-time.

As IBM has informed us, there is an environmental situation where
you're highly encouraged to use dynamic SQL. If you have the same table
name in more than one library and you are manipulating your library list
to control which table is accessed, IBM says that static SQL plan caches
and/or open data paths may not be rebuilt when switching library lists.
IBM says that if you use dynamic SQL then when you switch library lists
the plan caches and open data paths will definitely be rebuilt.

Sincerely,

Dave Clark
int.ext: 91078
direct: (937) 531-6378
home: (937) 751-3300

Winsupply Group Services
3110 Kettering Boulevard
Dayton, Ohio 45439 USA
(937) 294-5331





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