1.创建表dept1：
13:01:03 SCOTT@ORA11GR2>create table dept1 as select * from dept;
Table created.
13:01:40 SCOTT@ORA11GR2>select * from dept1;
DEPTNO DNAME LOC
---------- -------------- -------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON
13:02:22 SCOTT@ORA11GR2>insert into dept1 values(50,'xxx','xxxx'); 1 row created.
2.查看当前的scn：
13:04:12 SYS@ORA11GR2>select current_scn from v$database; CURRENT_SCN
-----------
1006836
3.删除表dept1：
13:07:51 SCOTT@ORA11GR2>delete from dept1; 4 rows deleted. 13:08:03 SCOTT@ORA11GR2>select * from dept1; no rows selected
4.基于scn的查询：
13:08:15 SCOTT@ORA11GR2>select * from dept1 as of scn 1006836;
DEPTNO DNAME LOC
---------- -------------- -------------
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON
50 xxx xxxx