RE: L-date fields null-Reply

[David Morris <dmorris@xxxxxxxxxxxxx>]

>>> Bob Cozzi <BobCozzi@ibm.net> 09/10 11:05 pm >>>

You know, people say there was never a year zero so 0000 is an invalid 
date. Okay, but I gotta believe that 0 is the value the comes before 1, so 
if 00010101 is a valid date why can't 0 be a null date value?

<< I agree that null values should not be validated.  It makes sense to me to
have the system set null values to the default value (system or DFT) or, if
specified, a value set with the ALWNULL DDS keywords.  That way nulls
could be implemented the same for different data type.  Null fields should be
set to this value.  For example, *LOVAL may be a better null value for
character fields than the default of *BLANKS.  It should be possible to specify
a null field that is not externally defined.  The null indicator should be 
handled
automatically if possible or via another compile (or file level) keyword.  If
handled automatically when a value is moved into a field it should set the null
off.  If *null is moved to the field it should be set to the null value (set on
alwnull or dft DDS) and the indicator set on.  The indicator attribute should be
considered part of the data for moves.

The ALWNULL compile option should also be allowed for SQL RPGIV.  Nulls
in SQL RPGIV should be able to use the built in function.   This is probably
available with V4.   Actually all new features introduced to RPGIV should be
implemented in SQL RPGIV or a BIG warning should be placed in the SQL
manual to identify areas that are not fully implemented.  We have lost many
hours over the years due to these undocumented release incompatibilities.

I haven't spent a lot of time thinking about nulls so I am probably missing
some points that make the current implementation make sense.  I have used
them enough to know they are problem areas.  I have faith the
implementation will improve.

David Morris
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