Hmm...there is an updateOrCreate method.

/**
 * Create or update a related record matching the attributes, and fill it with values.
 *
 * @param  array  $attributes
 * @param  array  $values
 * @return \Illuminate\Database\Eloquent\Model
 */
public function updateOrCreate(array $attributes, array $values = [])
{
    $instance = $this->firstOrNew($attributes);

    $instance->fill($values);

    $instance->save();

    return $instance;
}

I believe for this method, the first argument is for any matching attributes. The second argument is for the new values so you might able to do something like this.

$order->location()->updateOrCreate([], $arrayOfData);

Thanks for the info @thomastkim. I couldn't get that to work, my model is using a hasOne relationship which returns a HasOne class object, which is en extention of the base Relation class, which doesnt have the updateOrCreate method. Infact I couldnt find that method you posted anywhere in the laravel source. I am working with 4.2.

I was able to get close to what I am looking for by grabbing the related model directly,

// This will create the new row successfully
$order->location()->getRelated()->updateOrCreate(['data']);

// However the order still isn't aware of the new related row
var_dump($order->location);
// This outputs NULL even though the related row was created

// The only way to get the newly added location is to go
$location = $order->find(1)->location;
// This is an unnecessary database call

That is weird. HasOne extends HasOneOrMany, which does have the function.

But glad you got it to work! :)