Magento category URL empty in backend

Question

Our category URL in the backend is empty. But our sites work fine with the value that was there before. If I create a new category then I do see the URL key value. What can be causing this?

New category=URL key
Old category=no URL key empty

We investigated catalog_category_entity_varchar and saw that many category values were duplicated on a lower (store hierarchy) level. Strange.

Help or clues appreciated

Answer 1

I have no idea what happened without seeing code or poking through the db, but...
it may work because the urls come from the core_url_rewrites table.
You might still have values for the categories in there.
But you still need to investigate what happened to the url keys.
Maybe the db is corrupted.
Check if you have values in the catalog_category_entity_vacrchar for the url_key attribute.

You can get the id of the attribute like this:

SELECT *
FROM eav_attribute
WHERE attribute_code = 'url_key' AND
    entity_type_id = (SELECT 
                          entity_type_id 
                      FROM 
                          eav_entity_type
                      WHERE
                          entity_type_code = 'catalog_category')

Then get the id from the query above and run

SELECT * from catalog_category_entity_varchar where attribute_id = ID_FROM_QUERY_ABOVE

There is also the possibility that you still have values for the url keys at store view level, but you are missing the ones for the default values scope.
This way the website can function without any issues, but it creates confusion for the admins.