Database Exception – yii\db\Exception

                } else {
                    $this->pdoStatement->execute();
                }
                break;
            } catch (\Exception $e) {
                $rawSql = $rawSql ?: $this->getRawSql();
                $e = $this->db->getSchema()->convertException($e, $rawSql);
                if ($this->_retryHandler === null || !call_user_func($this->_retryHandler, $e, $attempt)) {
                    throw $e;
                }
            }
        }
    }

 
        $this->prepare(true);
 
        try {
            $profile and Yii::beginProfile($rawSql, 'yii\db\Command::query');
 
            $this->internalExecute($rawSql);
 
            if ($method === '') {
                $result = new DataReader($this);
            } else {
                if ($fetchMode === null) {
                    $fetchMode = $this->fetchMode;

     * @return string|int|null|false the value of the first column in the first row of the query result.
     * False is returned if there is no value.
     * @throws Exception execution failed
     */
    public function queryScalar()
    {
        $result = $this->queryInternal('fetchColumn', 0);
        if (is_resource($result) && get_resource_type($result) === 'stream') {
            return stream_get_contents($result);
        }
 
        return $result;
    }

            $this->offset = $offset;
 
            if ($e !== null) {
                throw $e;
            }
 
            return $command->queryScalar();
        }
 
        $command = (new self())
            ->select([$selectExpression])
            ->from(['c' => $this])
            ->createCommand($db);

        $modelClass = $this->modelClass;
        if ($db === null) {
            $db = $modelClass::getDb();
        }
 
        if ($this->sql === null) {
            return parent::queryScalar($selectExpression, $db);
        }
 
        $command = (new Query())->select([$selectExpression])
            ->from(['c' => "({$this->sql})"])
            ->params($this->params)
            ->createCommand($db);

    public function count($q = '*', $db = null)
    {
        if ($this->emulateExecution) {
            return 0;
        }
 
        return $this->queryScalar("COUNT($q)", $db);
    }
 
    /**
     * Returns the sum of the specified column values.
     * @param string $q the column name or expression.
     * Make sure you properly [quote](guide:db-dao#quoting-table-and-column-names) column names in the expression.

    protected function prepareTotalCount()
    {
        if (!$this->query instanceof QueryInterface) {
            throw new InvalidConfigException('The "query" property must be an instance of a class that implements the QueryInterface e.g. yii\db\Query or its subclasses.');
        }
        $query = clone $this->query;
        return (int) $query->limit(-1)->offset(-1)->orderBy([])->count('*', $this->db);
    }
 
    /**
     * {@inheritdoc}
     */
    public function setSort($value)

     */
    public function getTotalCount()
    {
        if ($this->getPagination() === false) {
            return $this->getCount();
        } elseif ($this->_totalCount === null) {
            $this->_totalCount = $this->prepareTotalCount();
        }
 
        return $this->_totalCount;
    }
 
    /**

    {
        if (!$this->query instanceof QueryInterface) {
            throw new InvalidConfigException('The "query" property must be an instance of a class that implements the QueryInterface e.g. yii\db\Query or its subclasses.');
        }
        $query = clone $this->query;
        if (($pagination = $this->getPagination()) !== false) {
            $pagination->totalCount = $this->getTotalCount();
            if ($pagination->totalCount === 0) {
                return [];
            }
            $query->limit($pagination->getLimit())->offset($pagination->getOffset());
        }
        if (($sort = $this->getSort()) !== false) {

     *
     * @param bool $forcePrepare whether to force data preparation even if it has been done before.
     */
    public function prepare($forcePrepare = false)
    {
        if ($forcePrepare || $this->_models === null) {
            $this->_models = $this->prepareModels();
        }
        if ($forcePrepare || $this->_keys === null) {
            $this->_keys = $this->prepareKeys($this->_models);
        }
    }
 

    /**
     * Returns the data models in the current page.
     * @return array the list of data models in the current page.
     */
    public function getModels()
    {
        $this->prepare();
 
        return $this->_models;
    }
 
    /**
     * Sets the data models in the current page.

    /**
     * Returns the number of data models in the current page.
     * @return int the number of data models in the current page.
     */
    public function getCount()
    {
        return count($this->getModels());
    }
 
    /**
     * Returns the total number of data models.
     * When [[pagination]] is false, this returns the same value as [[count]].
     * Otherwise, it will call [[prepareTotalCount()]] to get the count.

 
    /**
     * Runs the widget.
     */
    public function run()
    {
        if ($this->showOnEmpty || $this->dataProvider->getCount() > 0) {
            $content = preg_replace_callback('/{\\w+}/', function ($matches) {
                $content = $this->renderSection($matches[0]);
 
                return $content === false ? $matches[0] : $content;
            }, $this->layout);
        } else {

        try {
            /* @var $widget Widget */
            $config['class'] = get_called_class();
            $widget = Yii::createObject($config);
            $out = '';
            if ($widget->beforeRun()) {
                $result = $widget->run();
                $out = $widget->afterRun($result);
            }
        } catch (\Exception $e) {
            // close the output buffer opened above if it has not been closed already
            if (ob_get_level() > 0) {
                ob_end_clean();

    {
        $_obInitialLevel_ = ob_get_level();
        ob_start();
        ob_implicit_flush(false);
        extract($_params_, EXTR_OVERWRITE);
        try {
            require $_file_;
            return ob_get_clean();
        } catch (\Exception $e) {
            while (ob_get_level() > $_obInitialLevel_) {
                if (!@ob_end_clean()) {
                    ob_clean();
                }

                    $this->renderers[$ext] = Yii::createObject($this->renderers[$ext]);
                }
                /* @var $renderer ViewRenderer */
                $renderer = $this->renderers[$ext];
                $output = $renderer->render($this, $viewFile, $params);
            } else {
                $output = $this->renderPhpFile($viewFile, $params);
            }
            $this->afterRender($viewFile, $params, $output);
        }
 
        array_pop($this->_viewFiles);
        $this->context = $oldContext;

     * @throws InvalidCallException if the view cannot be resolved.
     * @see renderFile()
     */
    public function render($view, $params = [], $context = null)
    {
        $viewFile = $this->findViewFile($view, $context);
        return $this->renderFile($viewFile, $params, $context);
    }
 
    /**
     * Finds the view file based on the given view name.
     * @param string $view the view name or the [path alias](guide:concept-aliases) of the view file. Please refer to [[render()]]
     * on how to specify this parameter.

     * These parameters will not be available in the layout.
     * @return string the rendering result.
     * @throws InvalidArgumentException if the view file or the layout file does not exist.
     */
    public function render($view, $params = [])
    {
        $content = $this->getView()->render($view, $params, $this);
        return $this->renderContent($content);
    }
 
    /**
     * Renders a static string by applying a layout.
     * @param string $content the static string being rendered

        $args = $this->controller->bindActionParams($this, $params);
        Yii::debug('Running action: ' . get_class($this->controller) . '::' . $this->actionMethod . '()', __METHOD__);
        if (Yii::$app->requestedParams === null) {
            Yii::$app->requestedParams = $args;
        }
 
        return call_user_func_array([$this->controller, $this->actionMethod], $args);
    }
}

        }
 
        $result = null;
 
        if ($runAction && $this->beforeAction($action)) {
            // run the action
            $result = $action->runWithParams($params);
 
            $result = $this->afterAction($action, $result);
 
            // call afterAction on modules
            foreach ($modules as $module) {
                /* @var $module Module */

        $parts = $this->createController($route);
        if (is_array($parts)) {
            /* @var $controller Controller */
            list($controller, $actionID) = $parts;
            $oldController = Yii::$app->controller;
            Yii::$app->controller = $controller;
            $result = $controller->runAction($actionID, $params);
            if ($oldController !== null) {
                Yii::$app->controller = $oldController;
            }
 
            return $result;
        }

            $params = $this->catchAll;
            unset($params[0]);
        }
        try {
            Yii::debug("Route requested: '$route'", __METHOD__);
            $this->requestedRoute = $route;
            $result = $this->runAction($route, $params);
            if ($result instanceof Response) {
                return $result;
            }
 
            $response = $this->getResponse();
            if ($result !== null) {

    {
        try {
            $this->state = self::STATE_BEFORE_REQUEST;
            $this->trigger(self::EVENT_BEFORE_REQUEST);
 
            $this->state = self::STATE_HANDLING_REQUEST;
            $response = $this->handleRequest($this->getRequest());
 
            $this->state = self::STATE_AFTER_REQUEST;
            $this->trigger(self::EVENT_AFTER_REQUEST);
 
            $this->state = self::STATE_SENDING_RESPONSE;
            $response->send();