I'm using a magento 1.13.02 version and there is a feature called staging website in it. In which we can create some products in staging website and test them if we feel satisfy than we can merge them to main website.
When I try to merge the sites I got following log
*> Exception message: SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key
> constraint fails
> (`backup_magentocuat2`.`s_2b_11_catalog_product_website`, CONSTRAINT
> `FK_S_2B_11_CAT_PRD_WS_PRD_ID_CAT_PRD_ENTT_ENTT_ID` FOREIGN KEY
> (`product_id`) REFERENCES `catalog_product_entity` (`entity_)
> Trace: #0 /var/www/canon_staging/lib/Varien/Db/Statement/Pdo/Mysql.php(110):
> Zend_Db_Statement_Pdo->_execute(Array)*