code: public function loadDefaultValues($skipIfSet = true)
      {
          foreach (static::getTableSchema()->columns as $column) {
              if ($column->defaultValue !== null && (!$skipIfSet || $this->{$column->name} === null)) {
                  $this->{$column->name} = $column->defaultValue;
              }
          }
  
          return $this;
      }
docs: Loads default values from database table schema.
  
  You may call this method to load default values after creating a new instance:
  
  ```php
  // class Customer extends \yii\db\ActiveRecord
  $customer = new Customer();
  $customer->loadDefaultValues();
  ```
  
  @param bool $skipIfSet whether existing value should be preserved.
  This will only set defaults for attributes that are `null`.
  @return $this the model instance itself.