How to correctly insert a row into a table that has multiple primary keys?

Question

PHP

There is zend framework 1.12 and a model in which an array with three keys is used as a primary key

class Admin_Model_DbTable_Starring extends My_Db_Table
{
    protected $_name = 'starring';

    protected $_primary = array('play_id', 'person_id', 'role_id'); // если тут не массив, а строка с 1 ключом, то все норм
    protected $_rowClass = 'My_Db_Table_Row';
    public $prefix  = 'str';

    ...

A row is inserted into the table in this way (all parameters come as numbers, I checked):

$starringModel = new Admin_Model_DbTable_Starring();

    $row = $starringModel->createRow();
    $row->play_id = $play_id;
    $row->person_id = $person_id;
    $row->role_id = $role_id;
    $row->status = 2;

    $row->save();

The record is created normally, but after insertion, the server response throws out Notice Array to string conversion in /var/www/html/library/Zend/Db/Statement/Pdo.php on line 228
Such nonsense only with tables where there is more than 1 primary key : $_primary = array('play_id', 'person_id', 'role_id'). Where there is exactly 1 key and it is equal to the string, for example $_primary = 'play_id' everything is fine.
How to get rid of this Notice? Has anyone experienced this?

Answer 1

There cannot be more than one primary key.
Actually, it can't.
There can only be one primary key.
But the primary key can be composite.
Judging by the characteristic php E_NOTICE, in zend fw the composite primary key is specified in some other way, because the code tries to cast $_primary to a string and receives E_NOTICE for this.