Re: DDL Record Select

[Vern Hamberg <vhamberg@xxxxxxxxxxx>]

Sean

Dave wants a keyed, sorted LF with selection - that is a select/omit LF 
and is the only way to get all that in one object.

Now that object is not very well-suited to SQL. For SQL he should have 
both an view and an index or 2.

The view would have the selection criteria in a WHERE clause.

One index would support the view's selectivitiy. The other would do the 
sort. Now it might be possible to have both in one index - all the 
better. Depends on what those criteria are relative to the ordering.

With that, SQL can do very well. And RPG can use both a view and and 
index. However, there will be no builtin ordering with the view if used 
in an F-spec and no selectivity with the index (until 6.1) if used in an 
F-spec.

If he means to use the LF only in native RPG IO, then the select/omit is 
probably the best answer.

Later
Vern

McGovern, Sean wrote:
> If you are at V5R4 and want a logical file that performs record
> selection, and want to use DDL, you will need to use a view.
>
> But what happens when you want to select records with NCSTAT with a
> value other than 'D' ? You will need another view.
>
> The best approach, IMO, is to create 1 index with both NCSTAT and
> NCNPROD defined.
>
>
>
> -----Original Message-----
> From: midrange-l-bounces@xxxxxxxxxxxx
> [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
> daparnin@xxxxxxxxxxxxxx
> Sent: 15 March 2010 14:37
> To: Midrange Systems Technical Discussion
> Subject: RE: DDL Record Select
>
> Thanks to all for the responses.  We are at V5R4 so I will probably have
>
> to investigate the difference between an index and a view.  The end
> result 
> that I want is a keyed, sorted logical file that does record selection. 
> I'm trying to "modernize" my approach to such things but I'm still
> getting 
> up to speed.  Rob mentioned the record format.  I've been creating the 
> file with the record format name and then renaming it to the real file 
> name so the record format stays with what I want it to be.  I was
> thinking 
> that the ability to specify a record format name was a V6R1 thing.  As
> for 
> why we're not on V6R1, it basically hasn't bubbled up on the priority
> list 
> for those allocating the resources.
>
>
>
> Dave Parnin
>