Zend_Db_Table_Abstract::addReference PHP Method

    public function addReference($ruleKey, $columns, $refTableClass, $refColumns, $onDelete = null, $onUpdate = null)
    {
        $reference = array(self::COLUMNS => (array) $columns, self::REF_TABLE_CLASS => $refTableClass, self::REF_COLUMNS => (array) $refColumns);
        if (!empty($onDelete)) {
            $reference[self::ON_DELETE] = $onDelete;
        }
        if (!empty($onUpdate)) {
            $reference[self::ON_UPDATE] = $onUpdate;
        }
        $this->_referenceMap[$ruleKey] = $reference;
        return $this;
    }