get lastInsertId using PDO - php

Question

I am unable to get the lastInserId using PDO in php
$conn = new Db();
$query = "INSERT INTO orders SET
order_timestamp= :orderTimestamp ,
customer_id= :customerId";
$stmt = $conn->dbConnect()->prepare($query);
$stmt->bindParam(':orderTimestamp', date("Y-m-d H:i:s"), PDO::PARAM_STR);
$stmt->bindParam(':customerId', $_SESSION["customerId"], PDO::PARAM_INT);
$stmt->execute();
$orderId = $conn->lastInsertId();
return $orderId;
Below is the code used for DB Connection
public function dbConnect(){
try {
$conn = new PDO('mysql:host='.DBHOST.';dbname='.DBNAME, DBUSER, DBPASSWORD);
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
catch(PDOException $e) {
echo 'ERROR: ' . $e->getMessage();
}
return $conn;
}
I am getting an error as mentioned below.
Strict Standards: Only variables should be passed by reference in
H:\xampp\htdocs\php\tuf4\hunger\includes\classes\class.hunger.php on
line 31
Fatal error: Call to undefined method Db::lastInsertId() in
H:\xampp\htdocs\php\tuf4\hunger\includes\classes\class.hunger.php on
line 34

Answer 1

bindParam expects a variable, to be passed by reference. date("Y-m-d H:i:s") is clearly not a variable ;)
Try bindValue instead.
Using the correct function will stop the domino effect of errors, and allow you to get the lastInsertId you are seeking.
EDIT: On further review, you are trying to call lastInsertId on your Db wrapper class, not on the PDO object. Try:
$pdo = $conn->dbConnect();
$stmt = $pdo->prepare($query);
// ...
$orderId = $pdo->lastInsertId();