sommar@enea.se (Erland Sommarskog) (07/16/88)
I'm currently working with a database application for VMS and
we use DEC's own stuff, i.e. RDB (database), TDMS (form handler :-()
and CDD, Common Data Dictionary. In the CDD you store not only
the definitions of relations for RDB and forms and requests for
TDMS, but also record definitions.
Several VMS compilers recognizes a dictionary directive, so
you can include the record defintions in your 3rd generation
program. This means that you can take benefit of the CDD if you
for some reason want to pass data between modules written in
different languages.
This is nice, but one thing is missing: you can't define
constants with the CDD, so if my Cobol program which I call
from Pascal takes a control parameter I must double-declare
the constants for the codes. (Typically it had been an enumerate
in a Pascal-only system.) This is of course a source of error.
I would also like to use these constants within the CDD itself.
Take a field declared like:
Customer_name DATATYPE TEXT 30.
But somewhere in the RDB definitions there is a global field
defining the length of the name. If this length is changed, I
must remember to change all CDD definitions where "30" occurs.
The question after this lament is of course: Are there any products
that fulfils this requirement? Any database, any operating system
is of interest, since I'm just curious on "the state of the art".
And, yes, reply by mail. Don't clutter up three newsgroups with
"X does this perfectly". I'll summarize all interesting that drops
in. My address is sommar@enea.se. By path it is ...!uunet!enea!sommar
in America. In Europe change uunet to your national backbone.
--
Erland Sommarskog
ENEA Data, Stockholm
sommar@enea.UUCP
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