当Oracel的一个新功能出来的时候，我们可能不知道所有与此功能关联的数据字典名称，
那么如何才能得到这些 meta data 的 meta data 呢？
可以通过 dicitonary 来查看：
例如，查找所有 名字里带有 memory 的 数据字典名字列表：
SQL> col table_name for a30
SQL> col comments for a80
SQL>select table_name,comments from dictionary where table_name like '%MEMORY%';
TABLE_NAME COMMENTS
------------------------------ --------------------------------------------------------------------------------
DBA_HIST_MEMORY_RESIZE_OPS Memory Resize Operations History
DBA_HIST_MEMORY_TARGET_ADVICE Memory Target Advice History
V$INMEMORY_AREA Synonym for V_$INMEMORY_AREA
V$JAVA_LIBRARY_CACHE_MEMORY Synonym for V_$JAVA_LIBRARY_CACHE_MEMORY
V$LIBRARY_CACHE_MEMORY Synonym for V_$LIBRARY_CACHE_MEMORY
V$SGA_DYNAMIC_FREE_MEMORY Synonym for V_$SGA_DYNAMIC_FREE_MEMORY
GV$MEMORY_CURRENT_RESIZE_OPS Synonym for GV_$MEMORY_CURRENT_RESIZE_OPS
GV$MEMORY_DYNAMIC_COMPONENTS Synonym for GV_$MEMORY_DYNAMIC_COMPONENTS
GV$MEMORY_RESIZE_OPS Synonym for GV_$MEMORY_RESIZE_OPS
GV$MEMORY_TARGET_ADVICE Synonym for GV_$MEMORY_TARGET_ADVICE
GV$PROCESS_MEMORY Synonym for GV_$PROCESS_MEMORY
TABLE_NAME COMMENTS
------------------------------ --------------------------------------------------------------------------------
GV$PROCESS_MEMORY_DETAIL Synonym for GV_$PROCESS_MEMORY_DETAIL
GV$PROCESS_MEMORY_DETAIL_PROG Synonym for GV_$PROCESS_MEMORY_DETAIL_PROG
GV$RESULT_CACHE_MEMORY Synonym for GV_$RESULT_CACHE_MEMORY
GV$INMEMORY_AREA Synonym for GV_$INMEMORY_AREA
GV$JAVA_LIBRARY_CACHE_MEMORY Synonym for GV_$JAVA_LIBRARY_CACHE_MEMORY
GV$LIBRARY_CACHE_MEMORY Synonym for GV_$LIBRARY_CACHE_MEMORY
GV$SGA_DYNAMIC_FREE_MEMORY Synonym for GV_$SGA_DYNAMIC_FREE_MEMORY
GV$SQL_SHARED_MEMORY Synonym for GV_$SQL_SHARED_MEMORY
V$MEMORY_CURRENT_RESIZE_OPS Synonym for V_$MEMORY_CURRENT_RESIZE_OPS
V$MEMORY_DYNAMIC_COMPONENTS Synonym for V_$MEMORY_DYNAMIC_COMPONENTS
V$MEMORY_RESIZE_OPS Synonym for V_$MEMORY_RESIZE_OPS
TABLE_NAME COMMENTS
------------------------------ --------------------------------------------------------------------------------
V$MEMORY_TARGET_ADVICE Synonym for V_$MEMORY_TARGET_ADVICE
V$PROCESS_MEMORY Synonym for V_$PROCESS_MEMORY
V$PROCESS_MEMORY_DETAIL Synonym for V_$PROCESS_MEMORY_DETAIL
V$PROCESS_MEMORY_DETAIL_PROG Synonym for V_$PROCESS_MEMORY_DETAIL_PROG
V$RESULT_CACHE_MEMORY Synonym for V_$RESULT_CACHE_MEMORY
V$SQL_SHARED_MEMORY Synonym for V_$SQL_SHARED_MEMORY
SQL>