Re: Project ideas....

Hi Michael,

I've not seen performance problems with SYSCOLUMNS.

Some of the system catalog tables / views are slow, most are pretty fast.

Performance of those views can significantly vary depending on which
columns you're accessing, in particular which columns you're filtering on.

There are 3 sets of meta data tables and views:
1) DB2 for i catalog views (QSYS2)
2) ODBC and JDBC catalog views (SYSIBM)
3) ANS and ISO catalog views (QSYS2)

If you expand your meta data needs to using ALL the related tables and
views above, there is very little information missing from them.

I recently created a tool that would automatically upgrade a database from
an older structure to a newer one, by generating and running the SQL and
DDS statements needed. It uses about 95% SQL and 5% DDS / CL to accomplish
that. For generating the old school DDS, I did have to use APIs for some
of that. Other than that, I was very happy with the wealth of information
available in the catalog views.

There are redundant columns of meta data across those 3 sets of views. I do
recall cases where getting some of that redundant information was faster
from one catalog view versus another, but I don't recall which specific
ones were involved.

I use the catalog views first, and APIs as a last resort, for the simple
reason that coding to the APIs takes a lot longer, and require a much
larger volume of code.

Mike

On Tue, Aug 15, 2017 at 8:36 AM, <MichaelQuigley@xxxxxxxxxx> wrote:

"RPG400-L" <rpg400-l-bounces@xxxxxxxxxxxx> wrote on 08/14/2017 01:35:15
PM:

----- Message from "Birgitta Hauser" <Hauser@xxxxxxxxxxxxxxx> on
Mon, 14 Aug 2017 19:35:03 +0200 -----

To:

"'RPG programming on the IBM i \(AS/400 and iSeries\)'" <rpg400-
l@xxxxxxxxxxxx>

Subject:

RE: Project ideas....

Why not simply access the SYSCOLUMNS catalog view?

The system catalog views are rich with information, but lacks an index. It
grates against my nature searching for data without an index. I know Db2
for i can scan a million records in a hurry. But the APIs can give you the
exact record format, field, etc.

Using SYSCOLUMNS can you tell the order of the field, record format(s),
etc.? (I really would like to know.)

Perhaps I'm just missing an available index and some understanding, but
the API documentation is pretty clear.

Michael Quigley
Computer Services
The Way International
www.TheWay.org
--
This is the RPG programming on the IBM i (AS/400 and iSeries) (RPG400-L)
mailing list
To post a message email: RPG400-L@xxxxxxxxxxxx
To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/rpg400-l
or email: RPG400-L-request@xxxxxxxxxxxx
Before posting, please take a moment to review the archives
at http://archive.midrange.com/rpg400-l.

Please contact support@xxxxxxxxxxxx for any subscription related
questions.

Help support midrange.com by shopping at amazon.com with our affiliate
link: http://amzn.to/2dEadiD