constants
      filename="\\vip\\vpi\\programs\\register\\exe\\register.bin"
   domains
      db_selector=mydba
      mydom=city(zipcode,cityname);
                    person(firstname,lastname,street,zipcode,code)
      zipcode,cityname,firstname,lastname,street,code=string
   predicates
      listdba(db_selector)
      nondeterm bt_keys(db_selector,bt_selector,string,ref)
      nondeterm bt_keysloop(db_selector,bt_selector,string,ref)
   clauses
      listdba(Db_selector):-
      nl,
      write("********************************************"),nl,
      write("         Database listing"),nl,
      write("********************************************"),
      b_statistics(Db_selector,NoOfTerms,MemSize,DbaSize,FreeSize),nl,nl,
      write("Total number of records in the database: ",NoOfTerms),nl,
      write("Number of bytes used in main memory: ",MemSize),nl,
      write("Number of bytes used by the database: ",DbaSize),nl,
      write("Number of bytes free on disk: ",FreeSize),nl,
      fail.
   listdba(Db_selector):-
      db_chains(Db_selector,Chain),nl,nl,nl,nl,
      write("******** Chain LISTING *************") ,nl,nl,
      write("Name=",Chain),nl,nl,
      write("CONTENT OF: ",Chain),nl,
      write("------------\n"),
      chain_terms(Db_selector,Chain,mydom,Term,Ref),
      write("\n",Ref,":",Term),
      fail.
   listdba(Db_selector):-
      bt_btrees(Db_selector,Btree), % Возврат имени каждого B+ дерева
      bt_open(Db_selector,Btree,Bt_selector),
      bt_statistics(Db_selector,Bt_selector,NoOfKeys,
             NoOfPages,Dept,KeyLen,Order,PageSize),nl,nl,nl,
      write("******** INDEX LISTING **************") ,nl,nl,
      write("Name= ",Btree),nl,
      write("NoOfKeys= ",NoOfKeys),nl, 
      write("NoOfPages= ",NoOfPages),nl, 
      write("Dept= ",Dept),nl, 
      write("Order= ",Order),nl,
      write("KeyLen= ",KeyLen),nl, 
      write("PageSize= ",PageSize), nl, 
      write("CONTENT OF:",Btree),nl,
      write ("--------------\n"),
      bt_keys (Db_selector,Bt_selector,Key,Ref),
      write("\n",Key, " - ",Ref),
      fail.
   listdba(_).
   bt_keys(Db_selector,Bt_selector,Key, Ref):-
      key_first(Db_selector,Bt_selector,_),
      bt_keysloop(Db_selector,Bt_selector,Key,Ref).
   bt_keysloop(Db_selector,Bt_selector,Key,Ref):-
      key_current(Db_selector,Bt_selector,Key,Ref).
   bt_keysloop(Db_selector,Bt_selector,Key,Ref):-
      key_next(Db_selector,Bt_selector,_),
      bt_keysloop(Db_selector,Bt_selector,Key, Ref).
   goal
      db_open(mydba, filename,in_file),
      listdba(mydba).