Re: Views and Indexes

["Paul Tuohy" <tuohyp@xxxxxxxxxxxxx>]

Joel,

"Only SQL defined indexes are really accessible by traditional I/O" - yeesh,
I didn't put that very well!

Traditional I/O in RPG usually (but not always) implies you are accessing by
key (record address type of K on the F spec). You cannot specify the K for a
view (since it does not have a key).

You actually highlighted the "problem" with views - "the "where" and "order
by" capability of a view". The problem is you cannot specify an order by for
a view. When you can, life will be good :-).

You cannot define an index over a view.
When you can, life will be gooder :-)

I agree thoroughly about the functionality of views - which makes it even
more annoying that they are so difficult to use without embedded SQL. Guess
I want the best of both worlds :-)

Paul



----- Original Message -----
From: "Joel Cochran" <jrc@xxxxxxxxxx>
To: <midrange-l@xxxxxxxxxxxx>
Sent: Friday, July 23, 2004 6:06 PM
Subject: Re: Views and Indexes


>
> Paul,
>
> I stand clarified :-)
>
> I didn't say that indexes and views were the same thing: I know what
> capabilities a view has, but I was under the mistaken impression that
> because of the "where" and "order by" capability of a view that it
> represented the index as well.  I looked it up and sure enough a view is
> a "virtual table" that the underlying DBMS must execute at run time.
> This means that it has to find its own indexes.  So can you write an
> index over a View?
>
> I still don't think a logical can compete with the functionality of a
> view, but I'll admit I did under-represent them. "Only SQL
> defined indexes are really accessible by traditional I/O" - what do you
mean?
>
> Joel
> http://www.rpgnext.com
>