Get primary key name in eloquent model

Question

How to get name of primary key from model in laravel?

like this

dd(User::primaryKeyName()); // -> 'user_id'

I want to sort data on primary if 'order' is empty

$data = User::orderBy(Input::get('order', User::primaryKey()), 'ASC')->get();

but have

Non-static method Illuminate\Database\Eloquent\Model::getKeyName() should not be called statically, assuming $this from incompatible context

Answer 1

The fastest way to do this is probably like so:

(new User)->getKeyName();
(new User)->getTable();

However, I think the two approaches below provide a cleaner interface to the method.

The first approach uses a static method on your base model class:

class BaseModel extends Model
{
    protected static function KeyName() {
        return (new static)->getKeyName();
    }

    protected static function TableName() {
        return (new static)->getTable();
    }
}

Then inherit from this class in your model:

class ModelName extends BaseModel
{
    ...
}

And use like this: ModelName::KeyName();

If you don't have access to a base model class you can also use a trait:

trait EloquentGetTableNameTrait
{
    public static function TableName()
    {
        return (new static)->getTable();
    }
}

Which you use like this in your model:

class ModelName
{
    use EloquentGetTableNameTrait;

    ...
}

Unfortunately, all these approaches require instantiating an instance of the model, but there is currently no other way to retrieve this value.

Reference: https://github.com/laravel/framework/issues/1436

Answer 2

That method tries to get the value from a protected class property return $this->primaryKey; and $this needs a context from a class instance. If you really need to get that name dynamically, you could do this:

App::make('User')->getKeyName();

So your code would look something like this:

$data = User::orderBy(Input::get('order', App::make('User')->getKeyName()), 'ASC')->get();