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php – Why PDO Exception Error Not Caught?

Posted by: admin July 12, 2020 Leave a comment

Questions:

I have a PHP script with two deliberate typo mistakes in the statement for an SQL query:

try
{
 $stmt = $dbh->prepare("SELECT COUNT(*) FROM Product WHERE non-existent_column=?");
 $stmt->blindValue(1, $id, PDO::PARAM_INT);
 $stmt->execute();
 $row = $stmt->fetchColumn();
}
catch(PDOException $err)
{
 var_dump($err->getMessage());
 var_dump($dbh->errorInfo());
}

However, the script does not catch the error even after setting attribute to PDO::ERRMODE_EXCEPTION. What am I missing here?

UPDATE:

This is the full script. The second typo blindValue has been reverted back. The error remains uncaught:

<?php

$user= "user";
$password = "password";
$dsn = "mysql:dbname=Catalogue;host=localhost";
$dbh = new PDO($dsn, $user, $password);
$dbh->setAttribute(PDO::ERRMODE_EXCEPTION); 
$id = 1000;

try
{
 $stmt = $dbh->prepare("SELECT COUNT(*) FROM Product WHERE non-existent_column=?");
 $stmt->bindValue(1, $id, PDO::PARAM_INT);
 $stmt->execute();
 $row = $stmt->fetchColumn();
}
catch(PDOException $err)
{
 echo "caught";
 var_dump($err->getMessage());
 var_dump($dbh->errorInfo());
 exit();
}

var_dump($stmt);
var_dump($row);
echo "uncaught";
exit();

?>
How to&Answers:

Your call to setAttribute() lacks the first parameter:

$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 

If you didn’t get a

Warning: PDO::setAttribute() expects exactly 2 parameters, 1 given

your error_reporting level is too low for a development server and/or you didn’t keep an eye on the error log or didn’t set display_errors=On (which ever you prefer; I prefer the error log over display_errors).


edit: please try

<?php
echo 'php version: ', phpversion(), "\n";

try {
    $dbh = new PDO('mysql:host=localhost;dbname=test;charset=utf8', 'localonly', 'localonly');  
    echo 'client version: ', $dbh->getAttribute(PDO::ATTR_CLIENT_VERSION), "\n";
    echo 'server version: ', $dbh->getAttribute(PDO::ATTR_SERVER_VERSION), "\n";
    $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $dbh->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
}
catch(PDOException $err) {
    var_dump($err->getMessage());
    die('...');
}

$id = 'foo';

try
{
    $stmt = $dbh->prepare("SELECT COUNT(*) FROM Product WHERE `non-existent_column`=?");
    $stmt->bindValue(1, $id, PDO::PARAM_INT);
    $stmt->execute();
    $row = $stmt->fetchColumn();
}
catch(PDOException $err)
{
    var_dump($err->getMessage());
    var_dump($dbh->errorInfo());
    die('....');
}

echo 'done.';

printed on my machine

php version: 5.3.5
client version: mysqlnd 5.0.7-dev - 091210 - $Revision: 304625 $
server version: 5.5.8
string(94) "SQLSTATE[42S22]: Column not found: 1054 Unknown column 'non-existent_column' in 'where clause'"
array(3) {
  [0]=>
  string(5) "42S22"
  [1]=>
  int(1054)
  [2]=>
  string(54) "Unknown column 'non-existent_column' in 'where clause'"
}
....

Answer:

$stmt->blindValue(1, $id, PDO::PARAM_INT);

This should be $stmt->bindValue(1, $id, PDO::PARAM_INT);

You cannot catch Fatal Errors such as calling an undefined function/method.

Answer:

I experienced this and realized it was my PHP configuration file.

xdebug.show_exception_trace = 1

Exceptions will always appear if this is true.