DB2 Check Constraints - Reference a control file

[RNewton@xxxxxxxxxxxx]

I have been reading a lot today trying to figure out a way that I can setup
a check constraint for a 3a column in a table to reference a control file
that holds all the fields valid (allowed) values.

The control file has been around for years used by edit routines in RPG. It
has a key field that groups the records together. Then there is a values
field which holds the valid values. I would need to hit the file for a
certain group value in the key field then check if the value being inserted
into my table is found in the control file under that goup. The control
table has no "primary" keys. So setting up a foreign key constraint is
unsuccessful. Regardless, in a FKC there would be no way to specify the
group key value.

My goal is to be able to keep all of the valid values for validation in
this control file to ensure that I do not disturb existing processes and to
have one point in which to update them. I have tried setting up a check
constraint that does a subselect but I quickly learned that is outside of
the scope of a check condition.

Has anyone else tried to do this same thing before with any success?
Can you offer any insight on how I may accomplish this?

Thanks in advance,
Robert Newton
EDPS
Electronic Data Processing Services
Software Engineer
rnewton@xxxxxxxxxxxxxxxxx

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