RE: SQL Problem -- RPG400-L

Thanks, Bruce.

I have recently started using embedded sql so I am happy to learn better
and/or recommended ways of doing things.

I use * because it reduces typo's, and often I need the entire record
anyway.  You're saying, though, that this is a shortcut which I may pay for
later.  (and I probably saw it in a manual early on.)
Originally I was using SQLCOD to check for errors, etc, and have switched to
using SQL State because of recommendations from this list - probably from
you.

I didn't think there was any level checking ability but now I understand
what you were telling me because of *.

I did this test:  I created a file with 3 fields, and wrote an rpg pgm with
embedded sql to select * from file into :hostds.  The hostds is an external
ds.  Then I added a field to the file, and ran the program again (without
recompiling).  The hostds, which still contained only 3 fields, was inserted
correctly.  The fourth field was ignored or dropped apparently.  So I'm
still confused as to why it's bad to use *.

Thanks for responses.  I don't doubt you're right!  I want to understand the
"why" is all.  If you know of a particular good reference I'll be happy to
read it.  I've found a lot of references on the mechanics but not much on
recommended practices.

Thanks,

Phil





> >Alright Dr. Smith!
> >I have two questions:
> >1. How is it different (as far as level checking) from Mark's code?
>
> I am not sure what you mean, but in SQL, you should select the fields that
> you want/need and ignore the fields that you don't want/need.
>
> >2. How do you make the pgm fail with a level check error?
>
>
> In SQL, you don't. SQL and relation database technology is designed to
> isolate I/O from the physical structure of the data. The level check
> technology is based on native I/O where the I/O is related
> directly to, and
> reliant upon, the physical structure of the data. These are
> checked at open
> time. SQL does no such checking as the * is really a
> "convenience" item and
> not meant to be the programming construct for embedded applications.
>
> >Normally I use an external ds for my hostds.
>
>
> And you can still do this and maintain isolation, just so long as
> you don't
> then ask for all the fields (*) to be inserted into that structure. The
> field definitions are what you are after in that case and will apply, but
> the structure of the record as a whole is ignored.
>
> ===========================================================
> R. Bruce Hoffman, Jr.
>  -- IBM Certified Specialist - AS/400 Administrator
>  -- IBM Certified Specialist - RPG IV Developer
>
> "America is the land that fought for freedom and then
>   began passing laws to get rid of it."
>
>      - Alfred E. Neuman
>
>
>
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