Statement's errorCode() returns an empty string before execution, and '00000' (five zeros) after a sucessfull execution:
<?php
$stmt = $pdo->prepare($query);
assert($stmt->errorCode === '');
$stmt->execute();
assert($stmt->errorCode === '00000');
?>(PHP 5 >= 5.1.0, PHP 7, PHP 8, PECL pdo >= 0.1.0)
PDOStatement::errorCode — Recupera las informaciones sobre el error asociado durante la última operación sobre la consulta
Esta función no contiene ningún parámetro.
Idéntico a PDO::errorCode(), excepto que PDOStatement::errorCode() recupera únicamente los códigos de error para las operaciones sobre los objetos PDOStatement.
Ejemplo #1 Determina la categoría del error que ocurre
<?php
/* Provoca un error -- la tabla BONES no existe */
$err = $dbh->prepare('SELECT skull FROM bones');
$err->execute();
echo "\nPDOStatement::errorCode(): ";
print $err->errorCode();
?>El ejemplo anterior mostrará:
PDOStatement::errorCode(): 42S02
Statement's errorCode() returns an empty string before execution, and '00000' (five zeros) after a sucessfull execution:
<?php
$stmt = $pdo->prepare($query);
assert($stmt->errorCode === '');
$stmt->execute();
assert($stmt->errorCode === '00000');
?>Neither this property nor the PDOStatement::errorInfo() properties are available if you create  your own exception handler.
I am using PHP 5.2.4, PDO_INFORMIX 1.2.0.
Making this call at any point in the program after setting your own exception handler produces an error:
PHP Notice:  Undefined property:  PDOStatement::$errorCode in new_query.php on line
or
PHP Notice:  Undefined property:  PDOStatement::$errorInfo in new_query.php on line
But if I set the PDO to SILENT, only set error codes with:
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT)
Then process with if/else the call to this functions works fine.  The examples below only do error checking to show the result codes of this function.  Normally you would want more.
FAILS:
$dbh = new PDO("informix...")
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
try  {
      $result = $dbh->query("asdfkjasdfkjasdfjk");  /* obvious sql error */
      if ($result) print "success!";
      }
catch
      {
      $myeCode = $dbh->errorCode();
      /* do stuff with error */
      };
$dbh=0;
The error handler gets called but knows nothing about $dbh->errorCode or $dbh->errorInfo.
WORKS:
$dbh = new PDO("informix...")
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT);
$result = $dbh->query("asdfkjasdfkjasdfjk");  /* obvious sql error */
if ($result) 
      {
      /* process result */
      print "success!";
      /* all done, didn't make any changes */
      $dbh->rollback();
      }
else
      {
      $myeCode = $dbh->errorCode();
      print_r($myeCode);
      };
$dbh=0;  /* close connection */
I hope this helps someone else.
Cheers,
David