Analyzing the Yii error stack trace

When an error occurs, Yii can display the error stack trace along with the error. A stack trace is especially helpful when we need to know what really caused an error rather than just the fact that an error occurred.

Getting ready

1. Create a new yii2-app-basic application by using the Composer package manager, as described in the official guide at http://www.yiiframework.com/doc-2.0/guide-start-installation.html.
2. Configure a database and import the following migration:

   <?php
   use yii\db\Migration;
   class m160308_093234_create_article_table extends Migration
   {
       public function up()
       {
           $this->createTable('{{%article}}', [
               'id' => $this->primaryKey(),
               'alias' => $this->string()->notNull(),
               'title' => $this->string()->notNull(),
               'text' => $this->text()->notNull(),
           ]);
       }
   
       public function down()
       ...