UPDATE an array using PDO - php

Question

I'm creating a multi-step form for my users. They will be allowed to update any or all the fields. So, I need to send the values, check if they are set and if so, run an UPDATE. Here is what I have so far:
public function updateUser($firstName, $lastName, $streetAddress, $city, $state, $zip, $emailAddress, $industry, $password, $public = 1,
$phone1, $phone2, $website,){
$updates = array(
'firstName' => $firstName,
'lastName' => $lastName,
'streetAddress' => $streetAddress,
'city' => $city,
'state' => $state,
'zip' => $zip,
'emailAddress' => $emailAddress,
'industry' => $industry,
'password' => $password,
'public' => $public,
'phone1' => $phone1,
'phone2' => $phone2,
'website' => $website,
);
Here is my PDO (well, the beginning attempt)
$sth = $this->dbh->prepare("UPDATE user SET firstName = "); //<---Stuck here
$sth->execute();
$result = $sth->fetchAll(PDO::FETCH_ASSOC);
return $result;
Basically, how can I create the UPDATE statement so it only updates the items in the array that are not NULL?
I thought about running a foreach loop like this:
foreach($updates as $key => $value) {
if($value == NULL) {
unset($updates[$key]);
}
}
but how would I write the prepare statement if I'm unsure of the values?
If I'm going about this completely wrong, please point me in the right direction. Thanks.

Answer 1

First of all, use array_filter to remove all NULL values:
$updates = array_filter($updates, function ($value) {
return null !== $value;
});
Secondly, bind parameters, that makes your live a lot easier:
$query = 'UPDATE table SET';
$values = array();
foreach ($updates as $name => $value) {
$query .= ' '.$name.' = :'.$name.','; // the :$name part is the placeholder, e.g. :zip
$values[':'.$name] = $value; // save the placeholder
}
$query = substr($query, 0, -1).';'; // remove last , and add a ;
$sth = $this->dbh->prepare($query);
$sth->execute($values); // bind placeholder array to the query and execute everything
// ... do something nice :)

Answer 2

The below can be optimized:
$i = 0; $query = array();
foreach($updates as $key => $value) {
if ($value != NULL) {
$query[] = "{$key} = :param_{$i}";
$i++;
}
}
if (! empty($query)) {
$finalQuery = implode(",", $query);
$sth = $this->dbh->prepare('UPDATE user SET ' . $finalQuery);
$i = 0;
foreach($updates as $key => $value) {
if ($value != NULL) {
$sth->bindParam(':param_'.$i, $value, PDO::PARAM_STR);
$i++;
}
}
}