update function in php - php

Question

I have a update function that for now updates the required changes to MySQL database when I run index.php.
This is updating my password buy not the name field, ive been over the code and can not work out why.
Any help is greatly appreciated.
Index that tells what id and fields to update with entered data
<?php
require_once 'core/init.php';
$userInsert = DB::getInstance()->update('users', 1, array(
'password' => 'newpass',
'name' => 'Ben'
));
Function in different php that updated database
public function update($table, $id, $fields) {
$set = '';
$x = 1;
foreach($fields as $name => $value) {
$set .= "{$name} = ?";
if($x < count($fields)) {
$set .= ',';
}
$x++;
}
$sql = "UPDATE {$table} SET {$set} = 'newpassword' WHERE id = {$id}";
if(!$this->query($sql, $fields)->error()) {
return true;
}
return false;
}
I believe it to be a small error or mistype but I can not see the problem.
As you can see bellow the password field has been changed but the name has not

Answer 1

public function update($table, $id, $fields) {
$set = '';
$x = 1;
foreach($fields as $name => $value) {
$set .= "{$name} = \"{$value}\"";
if($x < count($fields)) {
$set .= ',';
}
$x++;
}
$sql = "UPDATE {$table} SET {$set} WHERE id = {$id}";
if(!$this->query($sql, $fields)->error()) {
return true;
}
return false;
}

Answer 2

Simply use of prepare and execute in PDO:
$sql = 'UPDATE '. $table .' SET username = :username, password = :password WHERE id = '. $id;
$sth = $dbh->prepare($sql);
$sth->execute(array(
':username' => 'ben',
':password' => 'newpassword'
));

Answer 3

private function update($table, $primaryKey, $fields) {
$query = 'UPDATE `' . $this->table . '` SET ';
foreach ($fields as $key => $value) {
$query .= '`' . $key . '` = :' . $key . ',';
}
$query = rtrim($query, ',');
$query .= ' WHERE `' . $this->primaryKey . '` = :primaryKey';
$fields['primaryKey'] = $fields['id'];
$this->query($query, $fields);
}
An example of an update function. Attention mine is inside a class and the query is another function and passes as an object.