Description:
------------
When using a parameter marker with insert the insert fails
with assignment of null value to a not nullable column.
However, all columns in the table are defined with a default value. The same insert but with a hard coded value
works ok.

Reproduce code:
---------------
<?php
print "a - trying to connect...\n";
try
{
  $dbh = new PDO('odbc:zdb2lt01' , 'db2tst01', 'adg680');
  print "b - connect ok...\n";
  echo "Connected\n";
  $dbh->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
  $dbh->beginTransaction();
  $dbh->exec("insert into db2tst01.tjedms1 (kol2) values ('php-insert1')");
  echo "first insert ok \n";
  $dbh->commit();

  $stmt = $dbh->prepare("insert into db2tst01.tjedms1 (kol2) values ('php-insert2')");
  $stmt->bindParam();
  $stmt->execute();
  echo "second insert ok \n";
  $stmt = $dbh->prepare("insert into db2tst01.tjedms1 (kol2) values (:kol2)");
  $stmt->bindParam(1, $kol2, PDO::PARAM_STR, 10);
  $kol2 = 'php-insert3';
  $stmt->execute();
  echo "third insert ok \n";
  $dbh->commit();

} catch (PDOexception $e) {
  print_r($stmt->errorInfo());
  echo "Failed: " . $e->getMessage();
}

?>


Expected result:
----------------
all 3 inserts should be processed

Actual result:
--------------
only first 2 inserts processed.

third insert fails with:
Array
(
    [0] => 23502
    [1] => -407
    [2] => [IBM][CLI Driver][DB2/LINUXZ64] SQL0407N  Assignment of a NULL value to a NOT NULL column "TBSPACEID=785, TABLEID=4, COLNO=1" is not allowed.  SQLSTATE=23502
 (SQLExecute[-407] at /home/tje/php/php-5.1.4/ext/pdo_odbc/odbc_stmt.c:133)
    [3] => 23502
)