Unable to get error info with PDO in PHP - php

Question

I am in the process of learning PDO and am trying to implement it in my current project. When I used mysqli, I could get detailed info about any error using mysqli_error($connection). I googled at what the comparable for PDO would be and found this post, and decided to implement it in my code. However, I am unable to get any error messages even when I know there is an obvious error in the sql statement.
Relevant code:
class Database {
public $connection;
function __construct() {
$this->open_database_connection();
}
public function open_database_connection() {
try {
$this->connection = new PDO('mysql:host=' . DB_HOST . ';dbname=' . DB_NAME, DB_USER, DB_PASSWORD);
$this->connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$this->connection->setAttribute( PDO::ATTR_EMULATE_PREPARES, false);
} catch(PDOException $e) {
echo $e->getMessage();
die('Could not connect');
}
} // end of open_database_connection method
public function query($sql, $params = []) {
try {
$query = $this->connection->prepare($sql);
} catch (Exception $e) {
var_dump('mysql error: ' . $e->getMessage());
}
foreach($params as $key => $value) {
if ($key === ':limit') {
$query->bindValue($key, $value, PDO::PARAM_INT);
} else {
$query -> bindValue($key, $value);
}
}
try {
$query->execute();
} catch(Exception $e) {
echo 'Exception -> ';
var_dump($e->getMessage());
}
/*
DID NOT WORK:
if (!$query->execute()) {
print_r($query->errorinfo());
}*/
$result = $query->fetchAll(PDO::FETCH_ASSOC);
$this->confirm_query($result);
return $result;
} // end of query method
function confirm_query($query) {
if (!$query) {
die('mysql error: ');
}
}
When I run the code, I do get the "mysql error", but I do not get any details about it. What am I doing wrong?
Update: As requested, I am providing additional details below.
What I am trying to do is get the user's login detail to be verified. To that end, once the user inputs his credentials , this code runs:
if (isset($_POST['submit'])) {
$username = trim($_POST['username']);
$password = trim($_POST['password']);
//check the database for the user
$user_found = User::verify_user($username, $password);
Relevant code from the User class:
public static function verify_user($username, $password) {
global $db;
$username = $db->escape_string($username);
$password = $db->escape_string($password);
$values = [ ":username" => $username,
":password" => $password,
":limit" => 1
];
$result_array = self::find_this_query("SELECT * FROM users WHERE username=:username AND password=:password LIMIT :limit", true, $values);
return !empty($result_array)? array_shift($result_array) : false;
}
public static function find_this_query($sql, $prepared = false, $params = []) {
global $db;
$the_object_array = array();
$result = $db->query($sql, $params);
$arr_length = count($result);
for ($i = 0; $i < $arr_length; $i++) {
$the_object_array[] = self::instantiation($result[$i]);
}
return $the_object_array;
}
public static function instantiation($the_record) {
$the_object =new self; //we need new self because $the_record corresponds to one user!
foreach($the_record as $the_attribute => $value) {
if ($the_object->has_the_attribute($the_attribute)) {
$the_object->$the_attribute = $value;
}
}
return $the_object;
}
public function has_the_attribute($attribute) {
$object_properties = get_object_vars($this);
return array_key_exists($attribute, $object_properties);
}

Answer 1

You have to use PDO::errorInfo():
(...)
public function query($sql, $params = []) {
try {
$query = $this->connection->prepare($sql);
if( !$query )
{
$error = $this->connection->errorInfo();
die( "mysql error: {$error[2]}" );
}
} catch (Exception $e) {
var_dump('mysql error: ' . $e->getMessage());
}
(...)
}
PDO::errorInfo returns an array:
Element 0: SQLSTATE error code (a five characters alphanumeric identifier defined in the ANSI SQL standard);
Element 1: Driver-specific error code;
Element 2: Driver-specific error message.