http://download.oracle.com/docs/cd/B19306_01/server.102/b15658/appg_db_lmts.htm#sthref1005
http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/onlineredo.htm#sthref918
http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/statements_5004.htm#SQLRF01204
http://otndnld.oracle.co.jp/document/products/oracle10g/102/doc_cd/server.102/B19201-02/statements_5.html#12707
