text: alter table 
      dav_site_node_folder_map 
  drop constraint 
      dav_impls_folder_id_fk;
  
  alter table 
      dav_site_node_folder_map 
  add constraint 
      dav_impls_folder_id_fk 
          foreign key (folder_id) 
          references cr_folders 
              on delete cascade;
  