Re: Oracle Client 10g vs. Instant Client 10.2 (Windows XP)

From: Laurenz Albe <>
Date: 04 Nov 2008 08:28:18 GMT
Message-ID: <>

ddf <> wrote:
>> We have received a Windows application that
>> we are told requires "Oracle Client 10g" to run.
>> We tried downloading Oracle's Instant Client and
>> installed that, in the hopes that that would be enough,
>> and we are able to run queries using SQL*PLUS, so
>> we know the installation worked,
>> but the application cannot find the Oracle stuff: we
>> get the message
>> Oracle client and networking components were not found
>> Is there a way to get an application (apparently) compiled
>> with Oracle Client to run with Instant Client?

> Probably not, as the necessary dlls are not available.  You'll most
> likely need to perform an install of the full Oracle 10.2.0 client.


If the client needs Oracle Data Provider for .NET or the OLE Provider, Instant Client won't do. Same if you need utilities like SQL*Loader.

But if the Oracle client is used to establish a connection via OCI or JDBC or ODBC, it should work fine.

I guess that in this case the problem could be that the program uses some heuristics to determine whether there is a working client or not, and these heuristics check for some stuff that is not in Instant Client.

A well behaved program should try to access oci.dll and leave all the rest to Oracle.

To illustrate that, let me relate my experiences with the "Microsoft ODBC Driver for Oracle". This piece of, er, software was developed long ago and is out of support, so has never seen an Instant Client in its days. It stubbornly refused to work with Instant Client, and eventually I traced what it was doing and found that it does not only check for the presence of oci.dll, but for a few other random Oracle DLLs as well. Why I do not know, but that prevents it from recognizing Instant Client as a valid Oracle client.

Maybe the program also checks for Oracle registry keys or the ORACLE_HOME environment variable, things that you do not have in a sound Instant Client installation.

The error message you quote sounds vaguely familiar - which "Windows application" is that?

It might eb a good idea to ask the vendor.

Laurenz Albe Received on Tue Nov 04 2008 - 02:28:18 CST

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