PDO: Call to a member function fetch() on a non-object - php

Question

Feeling a little stupid to ask such a question, but this code block is driving me crazy.
function __construct() {
$db = new db();
$this->db = $db->pdo;
}
function getEmployeeDetails() {
$eid = $this->db->quote($this->eid);
try {
$sql = $this->db->query("
SELECT email, cnumber
FROM employees
WHERE EID = $eid
");
$r = $sql->fetch();
$this->email = $r[0];
$this->cnumber = $r[1];
}
catch (PDOException $e) {
throw new Exception("failed");
}
}
It doesn't throw an exception but fails inside the try block - "Call to a member function fetch() on a non-object".
var_dump of the statement object returns 'false'. Why?
I've tried running the query independently, inside MySql. It returns 1 row.

Answer 1

It's hard to tell whether you have done this, but PDO doesn't throw exceptions by default, except on connection failures. You have to specifically add this:
$this->db = $db->pdo;
$this->db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
Without this, errors that occur during the query will cause ->query() to return false and that's obviously not an object that will have the ->fetch() method. You can also specify this attribute as part of the constructor call.
Also, you could use prepared statements instead of using ->quote():
$stmt = $this->db->prepare("SELECT email, cnumber
FROM employees
WHERE EID = ?");
$stmt->execute(array($this->eid));
$r = $stmt->fetch();