Laravel Eloquent CANNOT Save Models with Composite Primary Keys

Question

When defining composite primary keys then calling save on an instanced model, an exception is thrown.

ErrorException (E_UNKNOWN) 
PDO::lastInsertId() expects parameter 1 to be string, array given

The error occurred at line 32

$id = $query->getConnection()->getPdo()->lastInsertId($sequence);

And here's the declaration of Model

class ActivityAttendance extends Eloquent {
    /**
     * The database table used by the model.
     *
     * @var string
     */
    protected $table = 'activity_attendance';

    /**
     * The primary key of the table.
     * 
     * @var string
     */
    protected $primaryKey = array('activity_id', 'username');

    /**
     * The attributes of the model.
     * 
     * @var array
     */
    protected $guarded = array('activity_id', 'username', 'guests');

    /**
     * Disabled the `update_at` field in this table.
     * 
     * @var boolean
     */
    public $timestamps = false;
}

Here's the code to create new record in Controller class.

$attendance                 = new ActivityAttendance;
$attendance->activity_id    = $activityId;
$attendance->username       = $username;
$attendance->save();

The version of Laravel I'm using is 4.2.11, the latest version yet. Maybe it's a bug of the Laravel Framework? — Haozhe Xie, Oct 27 '14 at 16:04
I think you've pretty much hit the nail on the head - Laravel cannot handle composite primary keys. You can define them, but as soon as it needs to use a key for relationships it will fail. I hear pivot tables without an ID column (i.e. primary is a composite key made up of the two IDs that are to be pivoted) are generally okay, but that's only because the belongsToMany code knows that there are likely to be two columns to be basing its stuff on. Even so, I define my pivot tables with a primary ID column just to be sure! — alexrussell, Oct 27 '14 at 16:24

user1669496 · Accepted Answer · 2014-10-27T16:54:17.390

I'm assuming this is a pivot table, in which case you shouldn't be working with the pivot table directly. Work with either the Activity or Attendance models using the methods on belongsToMany() to update the pivot table, sync(), attach(), detach(), etc...

If for some reason that is not possible because your pivot table also contains keys going elsewhere, you should remove the current primary key, add an id auto-increment primary key column and add a unique index to username, and activity_id.

You may be able to save it like this as well... might be worth a shot.

$attendance = ActivityAttendance::create(
    'activity_id' => $activityId,
    'username' => $username
);

I've solve this issue by using `belongsToMany()` function between models. BTW, the method ::create() cannot work for unknown reason. — Haozhe Xie, Oct 28 '14 at 02:15

score 0 · Answer 2 · answered Jul 22 '15 at 18:25

0

You can only use ::create() on attributes you listed in your model's fillable attribute.

class ActivityAttendance extends Model {
...
    protected $fillable = ['activity_id', 'username'];
...
}

answered Jul 22 '15 at 18:25

Jon Falcon

1

score 0 · Answer 3 · answered Jan 11 '16 at 07:17

In simple scenario one may also face same error. So when creating composite primary key in models you also need to override $incrementing property in your model definition. If not declared you'll also get exact same error i.e [ErrorException' with message 'PDO::lastInsertId() expects parameter 1 to be string].

Reason maybe Eloquent try to get value of last auto-number. However its true that Laravel don't have full support of composite keys and we are mostly bound to use Query Builder approach.

class ActivityAttendance extends Eloquent {
   ...
   protected $incrementing = false;
   ...
}

Laravel Eloquent CANNOT Save Models with Composite Primary Keys

3 Answers3

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