How to add foreign key from bundle_option to cms_block

gistfile1.txt

/** @var $installer Mage_Catalog_Model_Resource_Setup */
$installer = $this;

$installer->startSetup();
$installer->getConnection()->addColumn($installer->getTable('bundle/option'), 'block_id',
    array(
         'nullable' => true,
         'unsigned' => true,
         'type' => Varien_Db_Ddl_Table::TYPE_INTEGER,
         'comment' => 'Foreign key to Block'
    )
);

$installer->getConnection()
->addForeignKey($installer->getFkName('bundle/option', 'block_id', 'cms/block', 'block_id'), $installer->getTable('bundle/option'),
        'block_id', $installer->getTable('cms/block'), 'block_id',
        Varien_Db_Ddl_Table::ACTION_SET_NULL, Varien_Db_Ddl_Table::ACTION_CASCADE
    );


$installer->endSetup();