Q:

Php Artisan tinker wont save updated entry in table

PHP LARAVEL 5. So i want to the most recent item from the jobs table with a status of zero. For now i am just going to try to update job type. But it pulls the correct item i would want to update shown below. I try to update and save and get this error.
>>> $job=\App\Job::orderBy('created_at', 'desc')->where('status', 0)->where('created_at', '>', '$current_dt')->first()

=> <App\Job #000000006ea292f40000000026d13dc7> {
   job_id: "4",
   job_hash: "ujshdujsh",
   job_type: "ujshdujsh",
   parameters: "",
   created_at: "2015-03-16 17:41:07",
   updated_at: "2015-03-16 17:41:07",
   available_ts: "0000-00-00 00:00:00",
   status: "0"
   }

>>> $job->job_type='updated'
=> "updated"

>>> $job->save();
Illuminate\Database\QueryException with message 'SQLSTATE[42S22]: Column    not found: 1054 Unknown column 'id' in 'where clause' 
(SQL: update `jobs` set `job_type` = updated, `updated_at` = 2015-03-16 17:58:38 where `id` is null)'
>>> 

A:

http://laravel.com/docs/5.0/eloquent#basic-usage
protected $primaryKey = 'job_id';

