Oracle 从10g起就支持正则表达式了，开始时仅仅是 POSIX 的语法格式,后续的版本对部分 PERL格式的也支持了，这部分表达式包括：
OperatorDescription
/d
A digit character.
/D
A nondigit character.
/w
A word character.
/W
A nonword character.
/s
A whitespace character.
/S
A non-whitespace character.
/A
Matches only at the beginning of a string, or before a newline character at the end of a string.
/Z
Matches only at the end of a string.
*?
Matches the preceding pattern element 0 or more times (nongreedy).
+?
Matches the preceding pattern element 1 or more times (nongreedy).
??
Matches the preceding pattern element 0 or 1 time (nongreedy).
{n}?
Matches the preceding pattern element exactly n times (nongreedy).
{n,}?
Matches the preceding pattern element at least n times (nongreedy).
{n,m}?
Matches the preceding pattern element at least n but not more than m times (nongreedy).
以上可参考原文： http://download.oracle.com/docs/cd/E11882_01/server.112/e17118/ap_posix003.htm#CHDIHFJA
