Postgres odbc driver bug - Mailing list pgsql-interfaces

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