doctrine / dbal

    /**

     * {@inheritdoc}

     */

    public function getForeignKeyReferentialActionSQL($action)

    {

        $action = strtoupper($action);

        switch ($action) {

            case 'RESTRICT': // RESTRICT is not supported, therefore falling back to NO ACTION.

            case 'NO ACTION':

                // NO ACTION cannot be declared explicitly,

                // therefore returning empty string to indicate to OMIT the referential clause.

                return '';

            case 'CASCADE':

            case 'SET NULL':

                return $action;

            default:

                // SET DEFAULT is not supported, throw exception instead.

                throw new \InvalidArgumentException('Invalid foreign key action: ' . $action);

        }

    }

    /**

     * {@inheritDoc}

     *

     * @throws \InvalidArgumentException if unknown referential action given

     */

    public function getForeignKeyReferentialActionSQL($action)

    {

        $upper = strtoupper($action);

        switch ($upper) {

            case 'CASCADE':

            case 'SET NULL':

            case 'NO ACTION':

            case 'RESTRICT':

            case 'SET DEFAULT':

                return $upper;

            default:

                throw new \InvalidArgumentException('Invalid foreign key action: ' . $upper);

        }

    }

    /**

     * Obtains DBMS specific SQL code portion needed to set the FOREIGN KEY constraint