Why are navigation items saved in the database?

Filter wp_nav_menu_objects and add your custom items dynamically (see this example or this). You get the current list of items and the arguments wp_nav_menu() was with as parameters. Then you can just add new items or remove existing ones.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)