[chaley]

I'm not sure what you are trying to do. I assume you want to read and write author links in a script using the calibre API.

The correct API to use is in db.cache:

def set_link_map(self, field, value_to_link_map, only_set_if_no_existing_link=False):
        '''
        Sets links for item values in field.
        Note: this method doesn't change values not in the value_to_link_map

        :param field: the lookup name
        :param value_to_link_map: dict(field_value:link, ...). Note that these are values, not field ids.

        :return: books changed by setting the link

        '''

In your case the map would be

{author_name: link_value, ... }

If you are trying to use/export existing links then use

    def get_link_map(self, for_field):
        '''
        Return a dictionary of links for the supplied field.

        :param for_field: the lookup name of the field for which the link map is desired

        :return: {field_value:link_value, ...} for non-empty links
        '''

Here is a code sample that manipulates the author links.

from calibre.library import db as DB

lib_path = sys.argv[1]
db = DB(path = lib_path)
cache = db.new_api

# print all the links in the map
author_link_map = cache.get_link_map('authors')
for aut,link in author_link_map.items():
    print(aut, link)
    
print('*******************')
# Save the existing link for author 'A B'
existing_link = author_link_map.get('A B')
print('existing link', existing_link)
print('*******************')

# modify a link
new_links = dict()
new_links['A B'] = 'This is a new link' # Author named "A B" must exist
cache.set_link_map('authors', new_links)

# Test that it was changed
author_link_map = cache.get_link_map('authors')
print('New link:', author_link_map.get('A B'))
print('*******************')

# Now put the old link back
new_links['A B'] = existing_link
cache.set_link_map('authors', new_links)
author_link_map = cache.get_link_map('authors')
print('Restored link:', author_link_map.get('A B'))

If the above is in the file foo.py you would call it with

calibre-debug -e foo.py 'path_to_library'