Hi

I'm trying to populate the invoiceID by adding +1 to the previous number but it won't work. No error message, just a blank page.

Here's my code:

class Invoice extends DataObject {

static $db = array(
'InvoiceID' => 'Int'
);

public function populateDefaults() {

parent::populateDefaults();

$obj = Invoice::get()->sort('Created', 'ASC')->First();

$this->InvoiceID = $obj->InvoiceID+1;
}

}

Why isn't working?

What happens if there is no invoices in the system? (you should use $this->InvoiceID = ($obj) ? $obj->InvoiceID+1: 1);

Also this way you've implemented will not check for duplicates of anything like that. You could just just the automatic primary $ID key that is defined on every DataObject. Check your php error logs for any other syntax issues that could be causing an issue.