[DUG] Use of ODBC drivers

[Mark Howard]

Hi Allan

Yes, I've just read about that facility on

http://www.microsoft.com/technet/prodtechnol/sql/70/maintain/hetdata.mspx

Interesting that you found it slow.  Our app is really quite small with a couple of hundred thousand records on one side of the join and less than 100 records on the other.  How would this compare with your situation?

Mark
On Thu, 16 Jun 2005 14:55:04 +1200, Allan, Samuel <S.A.Allan at massey.ac.nz> wrote:

> 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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>>> Forest Production Systems Ltd
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>>>
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>>
>>
>
>
>



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