Correct url for categories

Hi all,
In WP 4.2 project I added taxonomy using register_taxonomy function like

$labels = array(
                    'name'=> _x( 'Category Artists&Songs', 'Taxonomy General Name', 'artists_songs' ),
                    'singular_name'=>_x( 'Category of Artists&Songs', 'Taxonomy Singular Name', 'artists_songs' ),
                    'menu_name'=> __( 'Categories', 'artists_songs' ),
                    'all_items' => __( 'Categories', 'artists_songs' ),
                    'parent_item'=> __( 'Parent category', 'artists_songs' ),
                    'parent_item_colon' => __( 'Parent category:', 'artists_songs' ),
                    'new_item_name' => __( 'New category', 'artists_songs' ),
                    'add_new_item' => __( 'Add new category', 'artists_songs' ),
                    'edit_item' => __( 'Edit category', 'artists_songs' ),
                    'update_item' => __( 'Update category', 'artists_songs' ),
                    'search_items' => __( 'Search', 'artists_songs' ),
                    'add_or_remove_items' => __( 'Add or remove category', 'artists_songs' ),
                    'choose_from_most_used'=> __( 'Choose from most used', 'artists_songs' ),
                    'not_found'=> __( 'Not found', 'artists_songs' ),
                );
                $args = array(
                    'labels'                     => $labels,
                    'hierarchical'               => true,
                    'public'                     => true,
                );
                register_taxonomy( 'artists_songs_tax', array( 'artists_songs' ), $args );

and to this taxonomy I added several rows in wp_terms and wp_term_taxonomy tables like :

INSERT INTOwp_terms(term_id,name,slug,term_group`) VALUES
(1, ‘Uncategorized’, ‘uncategorized’, 0),
…
(96, ‘Artists&Songs songs’, ‘artists-songs-songs’, 0);

INSERT INTO wp_term_taxonomy (term_taxonomy_id, term_id, taxonomy, description, parent, count) VALUES
(1, 1, ‘category’, ”, 0, 1),
…
(109, 96, ‘artists_songs_tax’, ‘Songs Category for all posts describing songs’, 0, 5);
`
I can open page of Uncategorized categories with url
http://local-wp-songs.com/category/uncategorized/

But I can not open pages of all my categories and any category with url like:
http://local-wp-songs.com/category/artists_songs/
http://local-wp-songs.com/category/artists-songs-songs/

Which is the correct way for this ?

Thanks!