[DUG] Use of ODBC drivers

[Allan, Samuel]

SQL Server will let you do your cross-database platform join. However,
it is quite a lot slower. I don't know how to set this up as our DBA it.
I understand he set up a reference to the other DB platform's ODBC
connection in the SQL Server DB. You can then refer to this database as
you would to another SQL Server DB in your SQL.

eg SQL.

select
   a.actual_volume,
   p.planned_volume,
   ...
from
   plan p,
   ACTUALDB..OWNER.actual a
where
   a.id = p.id

I have done SQL like this in Query Analyzer, but because it is so slow,
we have not done this in our applications.

-----Original Message-----
From: delphi-bounces at ns3.123.co.nz [mailto:delphi-bounces at ns3.123.co.nz]
On Behalf Of Mark Howard
Sent: Thursday, June 16 2005 2:12 p.m.
To: delphi at ns3.123.co.nz
Subject: Re: [DUG] Use of ODBC drivers


On Thu, 16 Jun 2005 13:41:04 +1200, Kyley Harris <kyleyharris at gmail.com>
wrote:

> ODBC is just a generic way of communicating with a database using SQL.
> If you can provide a ODBC driver for your dbisam then they will be
> able to access your data, but I don't believe you can do Cross joins
> over databases using it. (I could be wrong) Generally, if they are
> referring to your data they will store referential keys from your DB
> in their DB. and run 2 DB connections from their middleware etc.

So if you had :
DBISAM table "Actual" with fields Forest and ActualVolume
and
MS-SQL table "Plan" with fields Forest and PlannedVolume
you couldn't, for example do:

SELECT A.ActualVolume, P.PlannedVolume
 FROM Actual AS a
JOIN Plan AS p
ON a.Forest = p.Forest
?

But presumably you could read the DBISAM data into a TEMP MS-SQL table
and then do a join on it within MS-SQL?

Not quite sure what you mean by your last sentence, above, Kyley.

BTW there IS a supported DBISAM ODBC driver.

Thanks for the reply.

Mark



> As long as it is readonly, and there is a viable DBISAM SQL driver for
> ODBC you should have no problems at all, as long as you provide them
> the meta data.
>
> R.
> Kyley
>
> On 6/16/05, Mark Howard <mhoward at pslog.co.nz> wrote:
>> Hi All
>>
>> At one client site I have my application (written in D7) is connected
to a DBISAM database behind a DBISAM server.
>> This site wants to develop an in-house (Net/MS-SQL) application which
accesses other MS-SQL tables as well as my DBISAM tables (read-only).
>>
>> Rather than convert my app to MS-SQL it seems that a low cost
alternative would be for them to gain access to my data through an ODBC
driver.
>>
>> I have had no experience with ODBC and so I would be very interested
in hearing the experiences of others who do have direct experience in
reading data and presumably joining tables between MS-SQL databases and
other databases accessed through ODBC (not necessarily DBISAM).
>>
>> What IS possible?  What is not?
>> Is it robust?
>> Are there any gotchas?
>>
>> Are there any good resources that I can read up on?
>>
>> Thanks
>>
>> Mark
>>
>>
>> --
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>



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Creators of PSLog - A harvesting information system
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