[Info-vax] VMS Software: New US Mailing Address

[Arne Vajhøj]

On 10/12/2022 6:02 PM, Jan-Erik Söderholm wrote:
> Den 2022-10-12 kl. 23:50, skrev Arne Vajhøj:
>> On 10/12/2022 5:45 PM, Jan-Erik Söderholm wrote:
>>> Den 2022-10-12 kl. 23:43, skrev Arne Vajhøj:
>>>> On 10/12/2022 5:33 PM, Arne Vajhøj wrote:
>>>>> On 10/12/2022 4:20 PM, Bill Gunshannon wrote:
>>>>>> Using a compatibility layer and trying to make PostGres look like
>>>>>> RDB (or Oracle) would be a major mistake. Better to bite the bullet
>>>>>> and move into the current century.
>>>>>
>>>>> It is a tradeoff.
>>>>>
>>>>> There are benefits from doing things the standard way instead of
>>>>> doing it the compatibility way.
>>>>>
>>>>> But there are also huge cost of changing the client applications.
>>>>>
>>>>>>                                  I have never used RDB (I have
>>>>>> used Oracle) but I assume it supports EXEC SQL and the usual SQL
>>>>>> syntax.  If so, moving could be fairly easy.  If not, could be a
>>>>>> problem.  Of course, probably also depends on the language being 
>>>>>> used.
>>>>>
>>>>> It will indeed depend on the language and the API used.
>>>>>
>>>>> embedded SQL/C => relative easy (PgSQL has precompiler)
>>>>>
>>>>> embedded SQL/Cobol => maybe easy (an open source precompiler 
>>>>> supposedly exist and work)
>>>>>
>>>>> embedded SQL/Pascal, Fortran ... => major rewrite (precompilers are 
>>>>> not available)
>>>>
>>>> Also note that moving to the current century implies
>>>> moving from embedded SQL...
>>>
>>> To what?
>>
>> ORM
>> standard API (like ODBC, JDBC, DB API 2.0 etc.)
>> database specific API (for PGSQL that means libpq*)
>>
>> *) libpq is already ported to VMS - 
>> https://vmssoftware.com/products/libpq/
>>
>> Arne
> 
> OK. That works when you have a central database engine/server to
> send the request to. There is no such database engine/server in Rdb.
> 
> All database "work" is done within the user process. Well, apart from
> some management routines, automatic backups and such. But all normal
> data manipulations are done in each user process.
> 
> So there are no IPC or network latencys to concider.
> DLM coordinate accesses/locks and such.

The database access API and "network database" vs Rdb
"semi-embedded database" are really independent.

VMS Cobol embedded SQL to Rdb use "semi-embedded database" approach.

VMS Cobol embedded SQL to Oracle Classic use "network database" approach.

Java native JDBC driver to Rdb use "semi-embedded database" approach.

Java thin JDBC driver to Rdb use "network database" approach.

Arne