RE: SV: Embedded SQL

On Thu, 2005-05-12 at 18:06, Alan Campin wrote:
> Have to agree 100% with you there. Defeats the whole purpose of using SQL. 
> Data base independence. SQL should never bring anything in except what it 
> needs. 

How is using "Select *" not database independent?  As far as I know,
every implementation of SQL supports this feature.  And it doesn't
defeat the purpose of SQL, it just simplifies the statement when the
user really does want ALL fields.

Actually, NOT specifying the field names would be more database
independent.  Let's pretend you had two files on two different databases
with the exact same definitions.  One is on the 400 and one is on
SqlServer.  Because of the name length limitations, the 400 file has
"SHRTCRYPTC" names, but the SqlServer has "long_descriptive_names".  If
your statement specifies field names, then that statement could only be
used against that particular database, whereas "select *" would work
with both.

Granted, this is hypothetical, and yes you can assign longer names to
iSeries fields, but I'm just trying to make a point.  I don't think
using "select *" should be elevated to the same holy-war level as GOTO,
and statements like "lazy", "inexcusable", and "defeats the purpose"
seem to be pointing us in that direction.

Joel Cochran
http://www.rpgnext.com


> -----Original Message-----
> From: Wilt, Charles [mailto:CWilt@xxxxxxxxxxxx]
> Sent: Thursday, May 12, 2005 9:52 AM
> To: RPG programming on the AS400 / iSeries
> Subject: RE: SV: Embedded SQL
> 
> 
> Good point Joel, I for one wasn't aware of it.
> 
> However, it could still be a problem since depending on such behavior assumes 
> that columns will be added to the end of the file, unused columns will never 
> be removed and in general the order will never change.
> 
> If you really need every column, maybe using select * could be excused.  But 
> even then, it's simply the lazy way out.  It doesn't really take that much 
> effort to get a list of the fields a file.  What to me is inexcusable, is the 
> use of select * when you don't actually need all the fields.
> 
> Just my .02.
> 
> Charles Wilt
> iSeries Systems Administrator / Developer
> Mitsubishi Electric Automotive America
> ph: 513-573-4343
> fax: 513-398-1121
>  
> 
> > -----Original Message-----
> > From: rpg400-l-bounces@xxxxxxxxxxxx
> > [mailto:rpg400-l-bounces@xxxxxxxxxxxx]On Behalf Of Joel Cochran
> > Sent: Thursday, May 12, 2005 7:32 AM
> > To: RPG programming on the AS400 / iSeries
> > Subject: RE: SV: Embedded SQL
> > 
> > 
> > On Thu, 2005-05-12 at 16:07, Wilt, Charles wrote:
> > > Note however that while I've been guilty of using select * 
> > in an embedded SQL statement myself, it is _NOT_ recommended.
> > > 
> > > Basically, if you use select *, and the file changes then 
> > you need to recompile the program.
> > 
> > That depends on what SQLSTT condition you are testing.  If the file
> > changes, the SQLSTT will be '01503', so if you are testing 
> > for = '00000'
> > then this statement is true, but if you are testing for <> 
> > '02000' then
> > it should continue to work.  
> > 
> > > Related is of course the use of customer_ds as an 
> > externally defined DS.
> > 
> > Since this was copied at compile time, it should continue to work.
> > 
> > Joel
> > http://www.rpgnext.com
> > 
> 
> 
> 
>