Returning lastInsertId() from database class - php

Question

I am using a database class picked up from a tutorial on codecourse.com (I am just starting the migration from procedural to pdo) and I am slowly extending it to fit my needs. However, the one thing I cannot manage is to return the lastInsertId() to be used globally.
Using the register example from that tutorial
$user = new User();
$salt = Hash::salt(32);
try {
$user->create(array(
'username' => Input::get('username'),
'password' => Hash::make(Input::get('password'), $salt),
'salt' => $salt,
'firstname' => Input::get('first_name'),
'lastname' => Input::get('last_name'),
'joined' => date('Y-m-d H:i:s'),
'group' => 1
));
} catch(Exception $e) {
die($e->getMessage());
}
It is at this point that I want to get the lastInsertId() - the one of the just registered user. I am not sure whether it comes out of the Database class via the insert function
require_once 'core/init.php';
class DB {
private static $_instance = null;
private $_pdo,
$_query,
$_error = false,
$_results,
$_count = 0;
private function __construct() {
try {
$this->_pdo = new PDO('mysql:host=' . Config::get('mysql/host') . ';dbname=' . Config::get('mysql/db'), Config::get('mysql/username'), Config::get('mysql/password') );
} catch(PDOException $e) {
die($e->getMessage());
}
}
public static function getInstance() {
if(!isset(self::$_instance)) {
self::$_instance = new DB();
}
return self::$_instance;
}
public function query ($sql, $params = array()) {
$this->error = false;
if ($this->_query = $this->_pdo->prepare($sql)) {
$x = 1;
if(count($params)) {
foreach($params as $param) {
$this->_query->bindValue($x, $param);
$x++;
}
}
if($this->_query->execute()) {
$this->_results = $this->_query->fetchAll(PDO::FETCH_OBJ);
$this->_count = $this->_query->rowCount();
} else {
$this->_error = true;
}
}
return $this;
}
public function action ($action, $table, $where = array()) {
if (count($where) === 3) {
$operators = array('=', '>', '<', '>=', '<=');
$field = $where[0];
$operator = $where[1];
$value = $where[2];
if (in_array($operator, $operators)) {
$sql = "{$action} FROM {$table} WHERE {$field} {$operator} ?";
if(!$this->query($sql, array($value))->error()) {
return $this;
}
}
}
return false;
}
public function get ($table, $where) {
return $this->action('SELECT *', $table, $where);
}
public function delete ($table, $where) {
return $this->action('DELETE', $table, $where);
}
public function insert ($table, $fields = array()) {
$keys = array_keys($fields);
$values = '';
$x = 1;
foreach($fields as $field) {
$values .= '?';
if ($x < count($fields)) {
$values .= ', ';
}
$x++;
}
$sql = "INSERT INTO {$table} (`" . implode('`,`', $keys) . "`) VALUES ({$values})";
if (!$this->query($sql,$fields)->error()) {
return true;
}
echo $sql;
}
return false;
}
public function update ($table, $id, $fields = array()) {
$set = '';
$x = 1;
foreach ($fields as $name => $value) {
$set .= "{$name} = ?";
if ($x < count($fields)) {
$set .= ', ';
}
$x++;
}
$sql = "UPDATE {$table} SET {$set} WHERE id = {$id}";
if (!$this->query($sql,$fields)->error()) {
return true;
}
}
return false;
}
public function first () {
return $this->results()[0];
}
public function results () {
return $this->_results;
}
public function count () {
return $this->_count;
}
public function error () {
return $this->_error;
}
}
Or the User class via the create function
class User {
private $_db,
$_data,
$_sessionName,
$_cookieName,
$_isLoggedIn;
public function __construct($user = null) {
$this->_db = DB::getInstance();
$this->_sessionName = Config::get('session/session_name');
$this->_cookieName = Config::get('remember/cookie_name');
if (!$user) {
if (Session::exists($this->_sessionName)) {
$user = Session::get($this->_sessionName);
if ($this->find($user)) {
$this->_isLoggedIn = true;
} else {
//Logged out
}
}
} else {
$this->find($user);
}
}
public function update($fields=array(), $id = null) {
if (!$id && $this->isLoggedIn ()) {
$id = $this->data()->id;
}
if (!$this->_db->update('users', $id, $fields)) {
throw new Exception('There was a problem updating the account!');
}
}
public function create($fields) {
if (!$this->_db->insert('users', $fields)) {
throw new Exception('There was a problem creating an account!');
}
}
public function find($user=null) {
if ($user) {
$field = (is_numeric($user)) ? 'id' : 'username';
$data = $this->_db->get('users', array($field, '=', $user));
if ($data->count()) {
$this->_data = $data->first();
return true;
}
}
return false;
}
public function login($username=null, $password=null, $remember = false) {
if(!$username && !$password && $this->exists()) {
Session::put($this->_sessionName, $this->data()->id );
} else {
$user = $this->find($username);
if ($this->data()->password === Hash::make($password, $this->data()->salt)) {
Session::put($this->_sessionName, $this->data()->id);
if ($remember) {
$hash = Hash::unique();
$hashCheck = $this->_db->get('users_session', array('user_id', '=', $this->data()->id));
if (!$hashCheck->count()) {
$this->_db->insert('users_session', array(
'user_id' => $this->data()->id,
'hash' => $hash
));
} else {
$hash = $hashCheck->first()->hash;
}
Cookie::put($this->_cookieName, $hash, Config::get('remember/cookie_expiry'));
}
return true;
}
return false;
}
}
public function hasPermission ($key) {
$group = $this->_db->get('groups', array('id', '=', $this->data()->group));
if($group->count()) {
$permissions = json_decode($group->first()->permissions, true);
if ($permissions[$key] == true) {
return true;
}
}
return false;
}
public function exists () {
return (!empty($this->_data)) ? true : false;
}
public function logout () {
Session::delete($this->_sessionName);
}
public function data () {
return $this->_data;
}
public function isLoggedIn () {
return $this->_isLoggedIn;
}
}
I have tried in both but whenever I try to echo the lastInsertId() back out, nothing is returned. Any advice would be greatly welcomed. If the problem might be outside of these areas, I have uploaded the entire script to https://github.com/MargateSteve/login.
Thanks in advance
Steve

Answer 1

The insert() method of a database class should return insert id. Here is a relevant part for it:
public function insert ($table, $fields = array()) {
$this->query($sql,$fields);
return $this->_db->lastInsertId;
}
while create() method of a User class should create a user instance.
public function create($fields) {
$id = $this->_db->insert('users', $fields);
$this->find($id);
}
Note that insert() method is vulnerable to SQL injection.
And now you can use your newly created user all right
$user = new User();
$user->create(array(
'username' => Input::get('username'),
'password' => Hash::make(Input::get('password')),
'firstname' => Input::get('first_name'),
'lastname' => Input::get('last_name'),
'joined' => date('Y-m-d H:i:s'),
'group' => 1
));
echo $user->data['id'];
I hope you are looking not for the code to copy and paste but for the understanding. And I hope you understand the logic above.

Answer 2

Add a public variable to your DB class that will hold the last inserted record ID:
class DB {
public $lastInsertId = null;
In the same DB class modify the query method, where the actual insert happens so that you can grab the ID from PDO:
public function query ($sql, $params = array()) {
$this->error = false;
if ($this->_query = $this->_pdo->prepare($sql)) {
$x = 1;
if(count($params)) {
foreach($params as $param) {
$this->_query->bindValue($x, $param);
$x++;
}
}
if($this->_query->execute()) {
$this->lastInsertId = $this->_pdo->lastInsertId();
$this->_results = $this->_query->fetchAll(PDO::FETCH_OBJ);
$this->_count = $this->_query->rowCount();
} else {
$this->_error = true;
}
}
return $this;
}
On the code above this is the important line:
$this->lastInsertId = $this->_pdo->lastInsertId();
You are assigning the value of PDO::lastInsertId() to your lastInsertId instance variable, that way you can access it from wherever you instantiate a DB object.
Now, modify the user class to hold a variable called id as well, do not name it lastInsertId because its confusing; in this context you have one single instance of a user which represents a single user and hence id simply refers to this instance user id:
class User {
public $id = null;
Modify in this same User class the create method as well to grab the lastInsertId value from your db object instance:
public function create($fields) {
if (!$this->_db->insert('users', $fields)) {
throw new Exception('There was a problem creating an account!');
}
$this->id = $this->_db->lastInsertId;
}
Then you can access the user ID in your register.php file simply accesing the user instance variable e.g. $user->id :
try {
$user->create(array(
'username' => Input::get('username'),
'password' => Hash::make(Input::get('password'), $salt),
'salt' => $salt,
'firstname' => Input::get('first_name'),
'lastname' => Input::get('last_name'),
'joined' => date('Y-m-d H:i:s'),
'group' => 1
));
Session::flash('home', "You have registered with user ID $user->id");
Redirect::to('index.php');
} catch(Exception $e) {
die($e->getMessage());
}