[bbk5110] 第41集 第四章 Flashback Database 05

闪回数据版本查询->闪回数据归档查询，前者不可以跨越DDL操作，后者可以跨越.

SQL> l
  1  select versions_xid,to_char(versions_starttime,'yyyy-mm-dd hh24:mi:ss') versions_starttime,versions_endtime,empno,sal
  2  from emp
  3  versions between timestamp to_timestamp('2013-05-18 14:13:07','yyyy-mm-dd hh24:mi:ss') and maxvalue
  4  where empno < 10
  5*
SQL> /

VERSIONS_XID     VERSIONS_STARTTIME                       VERSIONS_ENDTIME                              EMPNO        SAL
---------------- ---------------------------------------- ---------------------------------------- ---------- ----------
09000100EF080000 2013-05-18 14:13:50                                                                        1       1000
03001B0009090000 2013-05-18 14:13:59                                                                        2       1000

SQL> insert into emp(empno,ename,sal,deptno) values(3,'zhangsan3',2000,30);

1 row created.

SQL> commit;

Commit complete.

select versions_xid,to_char(versions_starttime,'yyyy-mm-dd hh24:mi:ss') versions_starttime,versions_endtime,empno,sal
from emp
versions between timestamp to_timestamp('2013-05-18 14:13:07','yyyy-mm-dd hh24:mi:ss') and maxvalue
  4  where empno < 10;

VERSIONS_XID     VERSIONS_STARTTIME                       VERSIONS_ENDTIME                              EMPNO        SAL
---------------- ---------------------------------------- ---------------------------------------- ---------- ----------
030000001E090000 2013-05-19 09:22:30                                                                        3       2000
09000100EF080000 2013-05-18 14:13:50                                                                        1       1000
03001B0009090000 2013-05-18 14:13:59     

/**************************************************************************/

实验目的:在11gr2版本下，进行DDL操作(删除字段)之后，在闪回数据区中也会相应的自动改变.

实验环境:11gr2
/*************************************************************************/

SQL> create table t
  2  as
  3  select * from all_objects;

Table created.

SQL> alter table t flashback archive fbda_area_netstore;

Table altered.

SQL> set linesize 100;
SQL> desc t;
 Name                                                  Null?    Type
 ----------------------------------------------------- -------- ------------------------------------
 OWNER                                                 NOT NULL VARCHAR2(30)
 OBJECT_NAME                                           NOT NULL VARCHAR2(30)
 SUBOBJECT_NAME                                                 VARCHAR2(30)
 OBJECT_ID                                             NOT NULL NUMBER
 DATA_OBJECT_ID                                                 NUMBER
 OBJECT_TYPE                                                    VARCHAR2(19)
 CREATED                                               NOT NULL DATE
 LAST_DDL_TIME                                         NOT NULL DATE
 TIMESTAMP                                                      VARCHAR2(19)
 STATUS                                                         VARCHAR2(7)
 TEMPORARY                                                      VARCHAR2(1)
 GENERATED                                                      VARCHAR2(1)
 SECONDARY                                                      VARCHAR2(1)
 NAMESPACE                                             NOT NULL NUMBER
 EDITION_NAME                                                   VARCHAR2(30)

SQL> ALTER TABLE T DROP COLUMN STATUS;

Table altered.

SQL> desc t;
 Name                                                  Null?    Type
 ----------------------------------------------------- -------- ------------------------------------
 OWNER                                                 NOT NULL VARCHAR2(30)
 OBJECT_NAME                                           NOT NULL VARCHAR2(30)
 SUBOBJECT_NAME                                                 VARCHAR2(30)
 OBJECT_ID                                             NOT NULL NUMBER
 DATA_OBJECT_ID                                                 NUMBER
 OBJECT_TYPE                                                    VARCHAR2(19)
 CREATED                                               NOT NULL DATE
 LAST_DDL_TIME                                         NOT NULL DATE
 TIMESTAMP                                                      VARCHAR2(19)
 TEMPORARY                                                      VARCHAR2(1)
 GENERATED                                                      VARCHAR2(1)
 SECONDARY                                                      VARCHAR2(1)
 NAMESPACE                                             NOT NULL NUMBER
 EDITION_NAME                                                   VARCHAR2(30)

Transaction Schema Evolution

• DDL support for:
  • Add,drop,rename,and modify column
  • Drop and truncate partition
  • Rename and truncate table

• Flashback queries work across DDL changes.
• All other DDL is not automatically supported(seen nex slide).

Full Schema Evolution

Disassociate or associate procedures in the DBMS_FLASHBACK_ARCHIVE package:

• Disable Total Recall on specified tables and allow more complex DDL(upgrades,split tables,and so on).
• Enforce schema intergrity during assocation(Base talbe and history table must be the smae schema.)

Note:This function should be used with care and with the understanding that the archive can no longer be guaranteed to be immutable because the history could have been altered during the time of disassociation.