[Info-vax] Oracle Database vs Oracle/Rdb

[Neil Rieck]

On Saturday, June 22, 2019 at 6:29:48 PM UTC-4, Jan-Erik Söderholm wrote:
> Den 2019-06-22 kl. 18:52, skrev Neil Rieck:
> > On Wednesday, June 19, 2019 at 1:18:05 AM UTC-4, DTL wrote:
> >> from application/VMS--(local)--RDB/VMS to 
> >> application/VMS--(local)--OraDB/VMS.
> >> 
> >> The Customer wants (why? dunno yet) to "move from Rdb to Oracle" (sic)
> >> in the same environment, with no modifications whatsoever.
> > 
> > That may not be possible depending upon how the customer is using 
> > Oracle-RDB. Recall that RDB was developed by DEC as a successor to RMS.
> >  Certain DEC languages, like COBOL and BASIC, have builtin support for 
> > RMS while other DEC languages provide indirect RMS support via the 
> > linker.
> > 
> > To the best of my knowledge, no so-called DEC languages provide builtin
> >  support of RDB...
> 
> Not for Oracle either.
> 
> > ...but some very cool developer tools exist which will allow you to 
> > compile-in RDB support.
> 
> It is the standard Embedded SQL compiler (similar to what Oracle has) for
> the usual languages and the SQL Modular Language compiler (I do not think
> there is something similar for Oracle) that compiles pure SQL files into
> standard VMS object (OBJ) files.
> 
> Now, the main difference between Rdb and Oracle is the architecture.
> 
> Oracle has one (or multiple) central "database engine(s)" that does all
> the physical database file accesses, all the "DB-work". User processes
> sends their SQLs over to this central process to have it executed.
> 
> Rdb links the database handling code into each application and thus is
> running in the user process space. So after the locks has been got, all
> processing can be done in parallel from each process. And if that is
> against different storage areas (DB files), there is close to no resources
> shared between the different processes. One process can have fewer local
> buffers to cope with normal work and some other can have more buffers to
> cope with a larger batch run. All that (buffer and other configurations)
> is central in the DB engines in Oracle.
> 
> There is a central "Rdb Monitor" process, but that doesn't do any work,
> it just monitors Rdb and starts rollback processes if a user process
> dies, and similar servicing tasks.
> 
> > If your customer is not doing this then RDB is no different than 
> > Oracle-db or any other SQL product which means you will access the 
> > engine with a connector.
> > 
> 
> It would be highly surpricing if a long time Rdb user does not
> use either embedded SQL or the SQL Modular Language compiler.
> You can write calls using the SQL/Services (similar to SQL*Net
> in Oracle), but there is no reason as long as you stay within
> the local system.
> 
> 
> > Neil Rieck Waterloo, Ontario, Canada 
> > http://neilrieck.net/docs/openvms_notes_rms_rdb.html#rdb
> >

It's been more than a decade since I played with Oracle-Rdb but I seem to remember inserting all the requisite RDB statements into the VMS-BASIC source then running a pre-compiler. IIRC, that step created one, or more, object files which contained all the glue necessary to link VMS-BASIC (or any language) to RDB.

On a related note, I cam currently moving a huge amount of data from RMS to MariaDB. Since we have at least 100 VMS-BASIC programs are not able to be renovated at this time, I wrote my own API in "C" which I call from VMS-BASIC.

Has anyone here played with Python on any OS? Python has builtin support to easily connect to MySQL or MariaDB. One of my colleagues rewrote one of our server programs (written in VMS-BASIC then saving data data to RMS) to Python. Surprisingly, the Python program is smaller while yet faster.

http://neilrieck.net/demo_vms_html/openvms_demo_index.html#hybrid_basic_c_mariadb

This shows the hoops anyone will need to go through if something like an RDB pre-compiler is not available.

Neil Rieck
Waterloo, Ontario, Canada.
http://neilrieck.net