RE: Postgres odbc driver bug

Please try the latest driver 7.01.0005.
It solves several parameter handling problems.

regards,
Hiroshi Inoue
-----Original Message-----
From: pgsql-interfaces-owner(at)postgresql(dot)org
[mailto:pgsql-interfaces-owner(at)postgresql(dot)org]On Behalf Of Keith Millard
Sent: Tuesday, May 01, 2001 10:37 PM
To: 'pgsql-interfaces(at)postgresql(dot)org'
Subject: [INTERFACES] Postgres odbc driver bug

We have found a reproducible problem with the Postgres ODBC driver. It
has to do with the parameter replacement feature in the driver. Below is a
piece of test code that shows the problem. We were able to fix the problem
by making a change to execute.c in the ODBC driver code (attached).

odbc driver version : Found in both 6.50 and 7.01.0004.

postgresql database version : Found with both 7.0.2 and 7.0.3 versions of
Postgres.

Server Operating System: Windows2000

Client Operation System: Windows2000

Explanation of the odbc driver bug:

/*****************************************
* ERROR HAPPENS HERE:
* If we set the buffer that we binded to column "text1" now, it will
FAIL.
* The SQLExecute in doQuery() will succeed (finding 0 rows), and the
* SQLFetchScroll call will return SQL_NO_DATA_FOUND.
*
* This is because of a bug in the odbc driver. The call to
SQLNumResultCols
* will execute the query in the driver, but the buffer that is binded
is
* empty, so no rows will be found. This of course assumes that the
table
* doesn't contain any empty records for the "text1" column, which is
correct
* for our test. Then when we call SQLExcute, the driver will realize
it has
* already done the query work and will not do it again, even though
our
* buffer for parameter substitution has changed (next line of code
below
* this comment).
*****************************************/

Zip file is attached. The code is currently set up to fail, but I
describe in my comments that you can uncomment the code that sets the buffer
before SQLNumResultCols to make things will work.

Thanks for your attention,

Keith Millard