RE: DDL - Handling Nulls

Handling NULLs, although not trivial, is possible in all HLLs, including
RPG. In fact, you could also create a PF using DDS that allows NULLs
(ALWNUL keyword), not just DDL. Historically, people have avoided NULLs due
to extra programming involved.

Handling NULLs in SQL is much easier than in an HLL, as SQL was designed
with NULLs in mind. In fact, SQL could generate NULLs for some queries even
if tables don't allow NULLs (i.e. LEFT OUTER JOIN result set).

As to should you allow NULLs or not... it's really a call of a database
architect.
One thing I'd share is that even though it's a relatively simple concept,
I've encountered programmers that can't wrap their mind around it.

BTW, I think of NULL as an 'absence of value' or 'void'.

HTH, Elvis

Celebrating 11-Years of SQL Performance Excellence on IBM i, i5/OS and
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-----Original Message-----
Subject: DDL - Handling Nulls

We have been expirementing with DLL files lately and have run into an
issue regarding NULL values. Now, I know that SQL tables allow NULL as a
value for a field and it is considered a data type that can be used; and
that is different than a blank.

I also know that I can code the DDL up front to not allow nulls and
provide a default value, but is there a way to handle nulls in an RPG IV
program without having to recompile the DDL?

Just looking for as many options here as possible, knowing that the best
one is to code it right up front....