[Omaha.pm] DBI odbc question

["Ryan Stille" <rps@willcomminc.com>]

I am working on a script that inserts records into a Progress database.
The script connects via DBI and odbc.

As I loop through each potential record to import, I query the database
for some info.  Occasionally I get errors like this:

DBD::ODBC::st execute failed: [OpenLink][ODBC][Progress Server]Stale
request handle. Request was not opened or has been closed. (1253)
(SQL-S1000)(DBD: st_execute/SQLExecute err=-1) at ./siimport.pl line
170.
DBD::ODBC::st fetchrow_array failed: (DBD: no select statement currently
executing err=-1) at ./siimport.pl line 171.
DBD::ODBC::st execute failed: [OpenLink][ODBC][Progress Server]Stale
request handle. Request was not opened or has been closed. (1253)
(SQL-S1000)(DBD: st_execute/SQLExecute err=-1) at ./siimport.pl line
170.
DBD::ODBC::st fetchrow_array failed: (DBD: no select statement currently
executing err=-1) at ./siimport.pl line 171.
DBD::ODBC::st execute failed: [OpenLink][ODBC][Progress Server]Stale
request handle. Request was not opened or has been closed. (1253)
(SQL-S1000)(DBD: st_execute/SQLExecute err=-1) at ./siimport.pl line
170.
DBD::ODBC::st fetchrow_array failed: (DBD: no select statement currently
executing err=-1) at ./siimport.pl line 171.

On some of the queries I was able to switch from:
$sth = $dbh->prepare($query);
$rc = $sth->execute();
($si_owner) = $sth->fetchrow_array();

To:
($si_owner) = $dbh->selectrow_array($query);

Which make the problem go away for some reason.  I was not able to
change all the queries to use selectrow_array of course.  But after
googling the "select statement currently executing" I came up with this:

$dbh->{odbc_exec_direct} = 1;

Which made the problem go away completely.  But I'd really like to
understand why.  I hate to see this problem come up again when I put the
script into production.  The blurb from the documentation was no help:

odbc_exec_direct
Force DBD::ODBC to use SQLExecDirect instead of SQLPrepare() then
SQLExecute. There are drivers that only support SQLExecDirect and the
DBD::ODBC do() override doesn't allow returning result sets. Therefore,
the way to do this now is to set the attributed odbc_exec_direct. There
are currently two ways to get this: $dbh->prepare($sql, {
odbc_exec_direct => 1}); and $dbh->{odbc_exec_direct} = 1; When
$dbh->prepare() is called with the attribute "ExecDirect" set to a
non-zero value dbd_st_prepare do NOT call SQLPrepare, but set the sth
flag odbc_exec_direct to 1.


Thanks for any help.
-Ryan