Conference ulysse::rdb_vms_competition

990.0. "ADABAS -> Rdb migration ?" by NSDC::FEUILLET () Mon Sep 16 1991 13:33

We are currently working on an offer for a an international organization who
would like to make is current document management and publishing process 
migrating to an automated one based on a DEC solution.

My current problem concerns the existing database. The customer has an IBM 
ADABAS DB, NATURAL/CICS "real time" application, NATURAL batch processes.

The only thing we wants to keep is the contents of the ADABAS DB. I would like
to migrate to a VAX/VMS/Rdb environment. Notice that the new VAX machine will
not be installed on the same site than the IBM.

The existing DB is structured as:

	General info file (Adabas)
	Synomyms and terms file (Adabas)
	text files (VSAM) (a text is less than 10000 characters)

I have read in this conference that conversion of database from Adabas to Rdb
may be complex because Adabas is not relational and allows repeating fields 
and groups within a table.

What the customer suggests is:

	- to create a tape containing a "flat file" of the existing DB
		Is it easy to do that?
		Does any program exist to do that?

	- to write a program to "design" Rdb DB corresponding to the existing
	  Adabas DB
		How to do that ?
		If PREDICT data dictionary is used for Adabas DB, are we
		using similarly CDD+ for Rdb?
		Is there anything to take care of?
		I expect also to store the text files (VSAM) in seg strings
		(the best should be to store the text data in a way to be
		 processed with DECwrite later on). Conversion is required,
		 isn't it?
		
	- to use a "load utility" provided with Rdb, to load the DB in Rdb
		Which load utilities?

Is there a better (simpler) alternative? Any existing tools available? Any 
comments, suggestions?

If I had to take Rdb-multimedia instead of Rdb, this could involve a 
different migration process?

New applications will be written for Rdb (developpers hope to provide at least
the same capabilities than for Natural/Adabas (e.g. screen handling,...)

To interface Rdb we have Rally (our 4GL) what else? which can be compared to
NATURAL.

Through this conference I read something on products like DTF, VAXlink, 
RdbAccess and others, without a clear understanding of how to apply that to
my case.

Any hints/infos/experience will be greatly appreciated!

Regards, Alain
	

    If you are looking for a product like Natural as used on the IBM
    system why not consider VMS Natural. This has options to allow it
    to run against Rdb or RMS as well as an Adabas database.
    
    Whilst this solution means we get no software revenues for Rally
    it may be more attractive to the customer.
    
    If Natural/Rdb is used this can be used to read the IBM Adabas database
    directly using a product called Net-work from Software AG. This
    works via an SNA/Gateway typically and allows read and write access
    to the IBM Adabas database.
    
    Another alternative may be to keep the current data design and store
    it in a VMS Adabas database. This means we lose the Rdb business
    but the conversion effort is much less.
    
    Ian