RE: RPG, RPG400, & SQL

George,

Wow.... Sounds like you've got a *TON* of work ahead of you...... Good luck.

A1) SQL files are fully compatible with RPG, as ALL database files on the
iSeries are managed by DB2/400.  However, RPGIV is by far the most
compatible language for working with SQL data.  Field size limitations are a
concern in RPGII and RPGIII, as are null, date, time, timestamp, etc. data
types.  RPGIV opens up a lot of new capability that was difficult and/or
impossible to support in earlier versions of RPG.

A2) I think at a minimum, you must be using RPGIII (RPG/400) to support
date, time, timestamp, varying length character, and null data support.
However, working with some of these in RPGIII can be like pulling your teeth
out.  Pretty painful and requires a LOT of compiler options.  Support is
often too minimal to be really helpful (as in date-time types).  Again,
RPGIV really opens up a lot of options when dealing with SQL database files.

A3) Nulls.... A null field, technically, has no value.  That's why we have
to use a null indicator to tell us when a field is null.  Valid data *MAY*
exist in a null field (as in date fields), which means if we must support
null data, we have to explicitly test the state of the null indicator before
we use the field in any calculations or reports.  Nulls are tricky, even in
RPGIV, and I'd advise you to consider if you really need them in your apps.

A4) Not really sure.  You can perhaps use operations navigator to get to
that information.  You may be able to use the SQL system catalog database to
access this information as well.

I am not sure that any RPGII code will be acceptable.  RPGII does not allow
for external data definition, nor will it support many data types that are
common in SQL databases.  I think I'd again recommend RPGIV as it gives you
much better support for SQL only applications.  I not sure if Embedded SQL
is even possible in RPGII, so that probably leaves you out right there. You
have a lot of points to consider, many of which I didn't even mention, so
don't leap to any quick conclusions.  Best of luck...


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



-----Original Message-----
From: George J. Vitek [mailto:vitekg@ctpf.org]
Sent: Tuesday, March 05, 2002 9:43 AM
To: rpg400-l@midrange.com
Subject: RPG, RPG400, & SQL


--
[ Picked text/plain from multipart/alternative ]
I have what I hope are some basic questions re: creating/maintaining
files created and used by SQL.

Some background work performed thus far:
A) CREATE TABLE  results in  PF's
B) Create index results in a LF's
C) Have run some SQL against DDS created files,( input & output) no
problems so far. Very simple functions however.

Questions:
1) Can RPG, RPGII, RPGIV be used to populate tables created via SQL,
some  having Indexes?
2) Some values such as TIMESTAMP do not exist in RPGII. I assume these
can be built to look like a SQL or RPGIV results. The reason for asking
this is that I would like to use a conversion package to populate SQL
created files from existing AS/400 database files. This package
generates RPGII programs to move the data around, not RPGIV, but the
package has very many "Conversion Task Features" that make it a good
candidate for a file conversion tool.
3) What is the value of Numeric NULL?  Alpha NULL?
4) Is there any way to print  Filename alisas's generated for long names
by Create Table? DSPFD to an Outfile does not seem to do it. (V3R2)

The bottom line is that I would like to use this file conversion package
which generates RPGII programs to perform conversions from DDS created
database files to SQL created files. An alternative method is to use
RPGIV, as this would give access to all features such as TIMESTAMP, DATE
stuff, etc. The last alternative which should eliminate all questions is
to utilize SQL to Read and write the files.

The resulting application system will be a totally SQL client server
system. However, we expect to be able to access for input, any of the
sql files using RPGIV for inquiry and reporting purposes. We do not
expect to update the SQL files with anything other than SQL statements,
but it would be nice to know that we could if there was a need to do so
( like a programmer not being familiar with SQL).

RPGIV is a great language. I am assuming we will not eliminate its
usefulness by going to a SQL based system. Any comments appreciated.

Regards,

George Vitek
--

_______________________________________________
This is the RPG programming on the AS400 / iSeries (RPG400-L) mailing list
To post a message email: RPG400-L@midrange.com
To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/cgi-bin/listinfo/rpg400-l
or email: RPG400-L-request@midrange.com
Before posting, please take a moment to review the archives
at http://archive.midrange.com/rpg400-l.