Re: Oracle ODBC Drivers

Michael,

In my experience, there are several sources of problems.

One is the function coverage. The ODBC specification does not require 100% coverage.

The headache comes when you use ODBC via another layer such as DAO. For example, an ODBC driver must provide the following to open a dynaset:

SQLGetInfo, SQL_ODBC_VER must return > "01".

SQLGetInfo, SQL_SCROLL_OPTIONS must support SQL_SO_KEYSET_DRIVEN.

SQLGetInfo, SQL_ROW_UPDATES must return "Y".

SQLGetInfo, SQL_POSITIONED_UPDATES must support SQL_PS_POSITIONED_DELETE and SQL_PS_POSITIONED_UPDATE. If you use DAO with a driver that does not support Dynasets, JET pulls the entire result set onto your local computer. Me thinks JET is a bit too helpful.

Snapshot functionality requires SQLExtendedFetch support. The ODBC cursor library will detect when a driver does not support SQLExtendedFetch, and provide the necessary but very slow support.

Other problems are caused by the complexity of the ODBC spec. For example, a column can be bound, unbound, or rebound at any time, even after data has been fetched from the result set. This is like a major stress on the driver writer, as no dbms CLI supports this level of flexibility. The driver write needs to code the logic that remembers the request, and pass the request to the dbms in the right order. Things fall through the cracks, and what works with one ODBC driver doesn't work with the next.

I'm sorry that I can't give you any specific recommendations, all my experience is with 2.0 drivers.
The 3.0 specification required a major rewrite, so I expect they break in different places.

I believe Visigenic (aka Inprise) dropped its ODBC product line.

Kinda wordy, but I hope it helps,

     candi

> We are also searching for stable ODBC drivers. We are neither
> satisfied with Oracle nor Microsoft ODBC drivers. They are
> used for Oracle access from MS-Access, especially on outer-joins
> we encountered several problems. So we think on switching to
> Visigenic (or test it at least).
> What specific problems did you encounter on switching drivers?
> (In an optimistic view, the ODBC-API should be the same for all
> drivers, except for different compliance levels.)
> TIA Michael
>

-----== Posted via Deja News, The Leader in Internet Discussion ==----- http://www.dejanews.com/ Now offering spam-free web-based newsreading Received on Fri May 01 1998 - 13:55:30 CDT