Is there a 'non-mandatory' relationship in DB2 8 for Z/OS?

[BD]

I'm working with a data model which is managed in the AllFusion ERwin
tool.

Within the modeler, some of the FK relationships are 'non-mandatory' -
which is to say that for a given child value, a parent value is
optional. This is different from an optional child key, where the
child table allows null values - in this case it's the relation itself
that is optional. Strikes me as rather contrary to the principles of
RI...

From what I can find, there is no such provision in DB2. I generated
DDL from within the tool with a specific relation set as Mandatory,
and then as Optional - there was no difference in the generated RI
DDL, suggesting that this provision within the ERwin tool is
effectively ignored.

I did scour the online db2 documentation, checking as many different
books as I could find relevant references in the Master Index - and
found no reference to any provision like this.

Can anyone confirm whether such 'non-mandatory' RI exists within DB2?

Thanks,

BD

[Mark A]

"BD" <ro*********@gmail.comwrote in message
news:1b**********************************@y22g2000 prd.googlegroups.com...

Thanks for the response. Puts me somewhat at ease to hear a
confirmation that I wasn't missing something fundamental. Thanks!!

I am not sure if DB2 for z/OS has implemented it yet, but DB2 for LUW has
foreign keys that can be defined as (or altered to) "not enforced".

[BD]

On Jul 25, 1:30*pm, "Mark A" <[e-mail]:

"BD" <[e-mail] in message

news:1b**********************************@y22g2000 prd.googlegroups.com...

Thanks for the response. Puts me somewhat at ease to hear a
confirmation that I wasn't missing something fundamental. Thanks!!

I am not sure if DB2 for z/OS has implemented it yet, but DB2 for LUW has
foreign keys that can be defined as (or altered to) "not enforced".

According to the documentation, yes, the z/OS variant has had that
since version 8.

It looks as if the 'Allow nulls' option within the RI relationship in
ERwin isn't having any effect on the generated DDL. Looks like all
constraints are enforced by default. I'm not 100% positive that this
particular dialog in the tool is supposed to have this particular
effect on the DDL - but so long as I know what to expect, I guess it's
okay. ;)

Thanks!