RE: SQL Problem -- RPG400-L

I think the problem would surface in the FETCH xxx INTO list_of_fields or
DS. If you're doing SELECT *, but don't add the fields to your INTO list,
you won't have enough host variables to receive the returned record. Better
to name the fields you want in the SELECT. That way you're insulated from
file changes (excluding column deletes).  I'm not sure if field length
changes would necessarily cause runtime exceptions, but field truncation
could cause logic errors or produce invalid results.

Eric DeLong
Sally Beauty Company
MIS-Sr. Programmer/Analyst
940-898-7863 or ext. 1863



-----Original Message-----
From: Phil [mailto:sublime78ska@yahoo.com]
Sent: Friday, September 14, 2001 1:34 PM
To: rpg400-l@midrange.com
Subject: RE: SQL Problem


Then also:

select custid from cusmst into :@custid

where custid and @custid are 5A at compile time then custid is changed to
5,0.

If the pgm is not recompiled then there will be a run time error.

Correct?  If so I still don't understand why using * is bad form.  It seems
to me that using embedded sql at all is inherently less safe than using
native I/O.

Personally I have not been in a situation where the database was changed
(other than app's still under development) except for Y2K.  That may be why
I'm having a hard time seeing this.

Phil

> -----Original Message-----
> From: rpg400-l-admin@midrange.com [mailto:rpg400-l-admin@midrange.com]On
> Behalf Of MWalter@hanoverwire.com
> Sent: Friday, September 14, 2001 1:46 PM
> To: rpg400-l@midrange.com
> Subject: RE: SQL Problem
>
>
>
> Regardless of how you change the table, DDS or SQL, if you change the
> structure of the table, and the corresponding host DS is not changed. You
> run the risk of contaminating a field in the data structure.
> Maybe adding a
> field to a table was a bad example. Changing the field length of a field
> might be a better one. Here is a scenario.
>
> You have a table, say: CharField1 10, CharField2, 10, ZoneField1 5,0
> ZoneField2 5,0.
> You write a program specifying your table as the EXTNAME in your hostds.
>
> Now you change the length of CharField2 to 15. You don't compile the
> program. Your host ds still says that CharField2 is 10. When the record is
> fetched into HostDS, wouldn't ZoneField1 contain character data?
>
> Maybe I'm wrong about this. I haven't tried to prove it. If I am, by all
> means let me know.
>
>
> Thanks,
>
> Mark
>
>
> Mark Walter
> Sr. Programmer/Analyst
> Hanover Wire Cloth a div of CCX, Inc.
> mwalter@hanoverwire.com
> http://www.hanoverwire.com
> 717.637.3795 Ext.3040
>
> <SNIP>
>
> You can use ALTER TABLE in SQL to add a field. I THINK,  if  you add a
> field
> using ALTER TABLE and leave it null capable, your existing programs should
> continue to run without any problems.
>
>
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