Query to check the size of Oracle database

When we need to check to check the size of oracle database then

Query:- 
 SELECT
              ( SELECT sum(bytes)/1024/1024/1024 data_size from dba_data_files ) +
              ( SELECT nvl(sum(bytes),0)/1024/1024/1024 temp_size from dba_temp_files ) +
             ( SELECT sum(bytes)/1024/1024/1024 redo_size from sys.v_$log ) +
             ( SELECT sum(BLOCK_SIZE*FILE_SIZE_BLKS)/1024/1024/1024 controlfile_size from                  v$controlfile) "Size in GB"
from Dual;