How to save custom fields in DB (ps_product) Prestashop? - prestashop-1.6

Question

What else I need in order make some custom fields in Product class and save them in columns I created in ps_product table?
If get some errors like:
Unknown column 'price_recent1' in 'field list'
What I have done:
I tweaked **Product.php** in order to add the three fields:
...
class ProductCore extends ObjectModel
{
...
public $price_recent1;
public $price_recent2;
public $price_recent3;
...
'price_recent1' => array('type' => self::TYPE_STRING, 'shop' => true, 'validate' => 'isString'),
'price_recent2' => array('type' => self::TYPE_STRING, 'shop' => true, 'validate' => 'isString'),
'price_recent3' => array('type' => self::TYPE_STRING, 'shop' => true, 'validate' => 'isString'),
...
}
then in **mymodule.php** I added the displayAdminProductsExtra hook in order to display a Tab inside the product edit backoffice:
public function hookDisplayAdminProductsExtra($params)
{
global $smarty;
$product = new Product((int)Tools::getValue('id_product'));
if (Validate::isLoadedObject($product))
{
$this->context->smarty->assign(array(
'price_recent1' => $product->price_recent1,
'price_recent2' => $product->price_recent2,
'price_recent3' => $product->price_recent3));
return $this->display(__FILE__, 'views/templates/admin/mymodule.tpl');
}
}
and finally I display them in **mymodule.tpl** :
<div id="mymodule" class="panel product-tab">
<input type="hidden" name="submitted_tabs[]" value="mymodule" />
<h3 class="tab"><i class="icon-info"></i> {l s='MyModule'}</h3>
<div class="form-group">
<label class="control-label col-lg-3" for="price_recent1">
<span class="label-tooltip" data-toggle="tooltip" title="{l s='Recent Price #1'}"> {l s='Recent Price #1'}
</span>
</label>
<div class="col-lg-9">
<input type="text" id="price_recent1" name="price_recent1" value="{$product->price_recent1|htmlentitiesUTF8}"/>
</div><br>
<label class="control-label col-lg-3" for="price_recent2">
<span class="label-tooltip" data-toggle="tooltip" title="{l s='Recent Price #2'}"> {l s='Recent Price #2'}
</span>
</label>
<div class="col-lg-9">
<input type="text" id="price_recent2" name="price_recent2" value="{$product->price_recent2|htmlentitiesUTF8}"/>
</div><br>
<label class="control-label col-lg-3" for="price_recent3">
<span class="label-tooltip" data-toggle="tooltip" title="{l s='Recent Price #3'}"> {l s='Recent Price #3'}
</span>
</label>
<div class="col-lg-9">
<input type="text" id="price_recent3" name="price_recent3" value="{$product->price_recent3|htmlentitiesUTF8}"/>
</div><br>
</div>
<div class="panel-footer">
<i class="process-icon-cancel"></i> {l s='Cancel'}
<button type="submit" name="submitAddproduct" class="btn btn-default pull-right" disabled="disabled"><i class="process-icon-loading"></i> {l s='Save'}</button>
<button type="submit" name="submitAddproductAndStay" class="btn btn-default pull-right" disabled="disabled"><i class="process-icon-loading"></i> {l s='Save and stay'}
</button>
</div>
I also have made the appropriate columns in **ps_product** table.

Answer 1

Your override is invalid.
It should be:
class Product extends ProductCore
remember about cache from cache/class_index.php