CakePHP 是否支持跨多个模型的事务？

Question

我正在编写一个支持多种测量单位的应用程序。在极少数情况下，用户想要更改他们的测量系统，我需要运行一个查询，该查询应用乘数将应用程序中的每个单位列缩放到正确的测量系统。为了确保在此操作中出现问题时所有数据保持正常，我需要在事务中运行查询。

是否可以在 Cake 中执行包含覆盖多个模型的查询的事务？

到目前为止，我发现的只有 DataSource::begin/commit/rollback()，但它只支持针对单个模型的查询。

Answer 1

是的。我在我的应用模型中使用了此功能，以简化交易。

https://github.com/infinitas/infinitas/blob/dev/Model/AppModel.php#L677

    /**
     * @brief wrapper for transactions
     *
     * Allow you to easily call transactions manually if you need to do saving
     * of lots of data, or just nested relations etc.
     *
     * @code
     *  // start a transaction
     *  $this->transaction();
     *
     *  // rollback if things are wrong (undo)
     *  $this->transaction(false);
     *
     *  // commit the sql if all is good
     *  $this->transaction(true);
     * @endcode
     *
     * @access public
     *
     * @param mixed $action what the command should do
     *
     * @return see the methods for tranasactions in cakephp dbo
     */
    public function transaction($action = null) {
        $this->__dataSource = $this->getDataSource();
        $return = false;
        if($action === null) {
            $return = $this->__dataSource->begin($this);
        } else if($action === true) {
            $return = $this->__dataSource->commit($this);
        } else if($action === false) {
            $return = $this->__dataSource->rollback($this);
        }
        return $return;
    }

那么你可以这样做：

$saved = true;
$this->transaction();
$saved = $saved && $this->save($data);
$saved = $saved && $this->SomeOtherModel->save($data2);
$saved = $saved && $this->AnotherModel->save($data3);

if($saved){
$this->transaction(true);
    return $this->id;
}
$this->transaction(false);
return false;

您还可以执行以下更复杂的操作：

function save1(){

    $saved = true;
    $this->transaction();
    $saved = $saved && $this->save($data);
    $saved = $saved && $this->save2($data);


    if($saved){
        $this->transaction(true);
        return $this->id;
    }

    $this->transaction(false);
    return false;
}

cake 不支持嵌套事务，但你可以伪造它们

// this will use transactions if its called directly, but will allow a calling method to

// create and manage the transaction.

function save2($data){
    $saved = true;
    $transaction = $this->transaction(); // will only be true if not already started
    $saved = $saved && $this->save($data);

    if($transaction){ // if it was started here, finish it
        if($saved){
            $this->transaction(true);
            return true;
        }

        $this->transaction(false);
        return false;
    }

    return $saved; // return just the status so the other model will finish the transaction
}

为了清楚起见，您可以执行 ClassRegistry::init('SomeRandomModel')->save2() 之类的操作。交易不限于当前模型或相关模型。它适用于任何型号。