ENABLE_DDL_LOGGING从11g开始就有了，只不过在11.2.0.2和11.1.0.7有bug，该bug被描述为：
Bug 12938609 - ENABLE_DDL_LOGGING does not log RENAME table statements (文档 ID 12938609.8)
该bug在如下版本中被fix：
| The fix for 12938609 is first included in |
该参数设置为TRUE后，可以在alert日志中记录如下DDL语句，但是请注意，仅仅记录的是DDL执行的时间，不包括DDL语句在哪个客户端执行的等等信息
•ALTER/CREATE/DROP/TRUNCATE CLUSTER
•ALTER/CREATE/DROP FUNCTION
•ALTER/CREATE/DROP INDEX
•ALTER/CREATE/DROP OUTLINE
•ALTER/CREATE/DROP PACKAGE
•ALTER/CREATE/DROP PACKAGE BODY
•ALTER/CREATE/DROP PROCEDURE
•ALTER/CREATE/DROP PROFILE
•ALTER/CREATE/DROP SEQUENCE
•CREATE/DROP SYNONYM
•ALTER/CREATE/DROP/RENAME/TRUNCATE TABLE
•ALTER/CREATE/DROP TRIGGER
•ALTER/CREATE/DROP TYPE
•ALTER/CREATE/DROP TYPE BODY
•DROP USER
•ALTER/CREATE/DROP VIEW
如上来源：http://docs.oracle.com/cd/E11882_01/server.112/e40402/initparams085.htm#REFRN10302
下面做实验
[oracle@rhel63single ~]$ sqlplus lc0029999/aaaaaa
SQL*Plus: Release 11.2.0.4.0 Production on Wed Jun 10 00:11:32 2015
Copyright (c) 1982, 2013, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> show parameter ddl
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
ddl_lock_timeout integer 0
enable_ddl_logging boolean FALSE
SQL> alter system set enable_ddl_logging=true;
System altered.
SQL> show parameter ddl
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
ddl_lock_timeout integer 0
enable_ddl_logging boolean TRUE
SQL> show user
USER is "LC0029999"
SQL> create table t1 as select * from dba_objects where 1=2;
Table created.
SQL> alter table t1 rename to t11;
Table altered.
SQL>
可以看到，该参数是动态参数，可以在线修改。
此时的alert日志如下：
Wed Jun 10 01:38:35 2015
ALTER SYSTEM SET enable_ddl_logging=TRUE SCOPE=BOTH;
Wed Jun 10 01:39:17 2015
create table t1 as select * from dba_objects where 1=2
Wed Jun 10 01:40:03 2015
alter table t1 rename to t11
SQL> create table lc0039999.t1 as select * from dba_objects where 1=2;
Table created.
此时的alert日志如下：
Wed Jun 10 01:46:52 2015
create table lc0039999.t1 as select * from dba_objects where 1=2也就是说，alert日志中显示的DDL是完全照搬当时执行的命令，而不会把当时执行环境中的user信息给添加上。
