PHP PDO lastinsertid of previous function - php

Question

I feel like I'm really overly complicating this whole scenario. Hopefully somebody can help.
I have a form which submits data to two tables (items and uploads). The form data goes to items, and the attachment to uploads. Basically I'd like both tables to have a corresponding itemId column.
My two functions create() and uploadFile() both work. However, I'm not sure how to use the the lastInsertId value of $crud->create() in my variable named $itemId - see comments in my code.
Reduced versions of my functions are below, including comments.
class.crud.php
class crud {
private $db;
function __construct($DB_con) {
$this->db = $DB_con;
}
public function create($inv, $ip, $make){
$stmt = $this->db->prepare("INSERT INTO items (inv,ip,make) VALUES (:inv,:ip,:make");
$stmt->bindparam(":inv", $inv);
$stmt->bindparam(":ip", $ip);
$stmt->bindparam(":make", $make);
$stmt->execute();
return true;
}
public function uploadFile($itemId, $inv, $file, $file_type, $file_size) {
$stmt = $this->db->prepare("INSERT INTO uploads (itemId,inv,file,type,size) VALUES (:itemId,:inv,:file,:file_type,:file_size)");
$stmt->bindParam(":itemId", $itemId); // inserts 777
$stmt->bindParam(":inv", $inv);
$stmt->bindparam(":file", $file);
$stmt->bindparam(":file_type", $file_type);
$stmt->bindparam(":file_size", $file_size);
$stmt->execute();
return true;
}
}
add-data.php
if (isset($_POST['btn-save'])) {
$itemId = '777'; //this successfully inserts 777 into the uploads.itemId teble, but i'd like to insert the lastInsertId value of $crud->create()
$inv = $_POST['inv'];
$ip = $_POST['ip'];
$make = $_POST['make'];
$file = rand(1000, 100000) . "-" . $_FILES['file']['name'];
$file_loc = $_FILES['file']['tmp_name'];
$file_size = $_FILES['file']['size'];
$file_type = $_FILES['file']['type'];
$folder = "uploaded_files/";
if ($crud->create($inv, $ip, $make)) {
echo 'success';
} else {
echo 'error';;
}
if (move_uploaded_file($file_loc, $folder . $file)) {
$crud->uploadFile($itemId, $inv, $file, $file_type, $file_size);
}
}
<form method='post' enctype="multipart/form-data">
<input type='text' name='inv'>
<input type='text' name='ip'>
<input type='text' name='make'>
<input type='file' name='file'>
<button type="submit" name="btn-save"></button>
</form>
The structure of both my tables are as follows;
items (itemId is primary, unique and auto-increment)
+--------+---------+-----------------+-------+
| itemId | inv | ip | make |
+--------+---------+-----------------+-------+
| 1 | 1293876 | 123.123.123.123 | Dell |
+--------+---------+-----------------+-------+
| 2 | 4563456 | 234.234.234.234 | Dell |
+--------+---------+-----------------+-------+
| 3 | 7867657 | 345.345.345.345 | Apple |
+--------+---------+-----------------+-------+
items (upload_id is primary, unique and auto-increment)
+-----------+--------+-----+----------+------------+------+
| upload_id | itemId | inv | file | type | size |
+-----------+--------+-----+----------+------------+------+
| 56 | 777 | 123 | test.txt | text/plain | 266 |
+-----------+--------+-----+----------+------------+------+
| 57 | 777 | 123 | test.txt | text/plain | 266 |
+-----------+--------+-----+----------+------------+------+
| 58 | 777 | 123 | test.txt | text/plain | 266 |
+-----------+--------+-----+----------+------------+------+
Please forgive the messy code. I'm just trying to get the logic correct and then I can work on it.
Any advice is appreciated.

Answer 1

So with help from #Maximus2012 I was able to solve this.
I changed my create() function to return lastInsertId() in place of just true or false. Then, I assigned the value returned by the create() function to a variable rather than using a static value.
So my working code now looks like this;
public function create($inv, $ip, $make){
$stmt = $this->db->prepare("INSERT INTO items (inv,ip,make) VALUES (:inv,:ip,:make");
$stmt->bindparam(":inv", $inv);
$stmt->bindparam(":ip", $ip);
$stmt->bindparam(":make", $make);
$stmt->execute();
return $this->db->lastInsertId();
}
Then in my add-data.php page I simply changed one vcariable to the following;
$itemId = $crud->create($inv, $ip, $make);
Solved.