11g’s Metadata Information for SQL Built-In Operators and Functions

11g introduced two new views: V$SQLFN_METADATA and V$SQLFN_ARG_METADATA, which provide metadata for all Oracle SQL built-in operations and functions.

SQL> set linesize 2500
SQL> SELECT * FROM v$sqlfn_metadata where name = 'REGEXP_SUBSTR' ;

   FUNC_ID NAME                              MINARGS    MAXARGS DATATYPE VERSION      ANA AGG DISP_TYPE     USAGE                          DESCR
---------- ------------------------------ ---------- ---------- -------- ------------ --- --- ------------- ------------------------------ ------------------------------
       526 REGEXP_SUBSTR                           2          5 STRING   V10 Oracle   NO  NO  NORMAL

SQL> SELECT * FROM v$sqlfn_arg_metadata WHERE func_id = 526 ;

   FUNC_ID     ARGNUM DATATYPE DESCR
---------- ---------- -------- ------------------------------
       526          1 STRING
       526          2 STRING
       526          3 NUMERIC
       526          4 NUMERIC
       526          5 STRING

This new feature may help especially to third party tools to maintain the function usage metadata redundantly in the application layer. For more informations you may check the documentation and this oracle-developer.net article.