Using before and after for transactions

beforeAfter.php

<?php

/**
 * @property int $bit_id
 */
class Thing extends CActiveRecord {
}

/**
 * @property int $id
 * @property Thing[] $things
 */
class Bit extends CActiveRecord {

    public function relations() {
        return array(
            'things' => array(self::HAS_MANY, 'Thing', 'bit_id'),
        );
    }

    /**
     * This is an example function that another model method or a controller might use.
     *
     * @param Thing[] $things
     * @return bool true on success
     */
    public function saveThings($things) {
        $curTr = Yii::app()->db->getCurrentTransaction();
        $transaction = $curTr === null || !$curTr->getActive()
            ? app()->db->beginTransaction()
            : false;
        try {
            // Begin of example task...
            if ($this->things)
                foreach ($this->things as $thing)
                    $thing->delete();
            if ($things)
                foreach ($things as $thing) {
                    $thing->bit_id = $this->id;
                    if (!$thing->save())
                        throw new CDbException('Cannot save a thing');
                }
            // ...end of example task.
            if ($transaction)
                $transaction->commit();
        } catch(Exception $e) {
            if ($transaction) {
                $transaction->rollback();
                Yii::log(__CLASS__ . '::' . __FUNCTION__ . '() failed');
                return false;
            } else
                throw $e;
        }
        return true;
    }

}




/**
 * @property int $id
 * @property Thing[] $things
 */
class Bit extends CActiveRecord {

    /**
     * @var CDbTransaction
     */
    protected $_transaction;

    public function relations() {
        return array(
            'things' => array(self::HAS_MANY, 'Thing', 'bit_id'),
        );
    }

    protected function beforeDelete() {
        $this->beforeChange();
        return parent::beforeDelete();
    }

    protected function beforeSave() {
        $this->beforeChange();
        return parent::beforeSave();
    }

    protected function afterDelete() {
        $this->afterChange();
        return parent::afterDelete();
    }

    protected function afterSave() {
        $this->afterChange();
        return parent::afterDelete();
    }

    /**
     * Begins a transaction if the caller of the model's method didn't already do so.
     */
    protected function beforeChange() {
        $transaction = Yii::app()->db->getCurrentTransaction();
        if (($transaction === null || !$transaction->getActive())
            && ($this->_transaction === null || !$this->_transaction->getActive())
        )
            $this->_transaction = Yii::app()->db->beginTransaction();
    }

    /**
     * If this model has a $this->_transaction then try to committ it and roll it
     * back if commit throws a CDbException.
     */
    protected function afterChange() {
        if ($this->_transaction !== null && $this->_transaction->active) {
            // Does Yii know to *not* call either afterDelete() or afterSave()
            // until the method has finished all its deletes, updates and saves?
            try {
                $this->_transaction->commit();
            } catch (Exception $e) {
                $this->_transaction->rollback();
                // Handle the error with some application logic, e.g. log it and
                // display an error message.
            }
        }
    }


    /**
     * This is an example function that another model method or a controller might use.
     *
     * @param Thing[] $things
     * @return bool true on success
     */
    public function saveThings($things) {
        // Handle the exceptions thrown by model manipulation here but
        // leave the commit to afterChnage().
        try {
            // Begin of example task...
            if ($this->things)
                foreach ($this->things as $thing)
                    $thing->delete();
            if ($things)
                foreach ($things as $thing) {
                    $thing->bit_id = $this->id;
                    if (!$thing->save())
                        throw new CDbException('Cannot save a thing');
                }
            // ...end of example task.
        } catch (Exception $e) {
            if ($this->_transaction !== null && $this->_transaction->getActive())
                $this->_transaction->rollback();
            else
                throw $e;
        }
    }
}