oracle rowid 研究

SQL> create table tab01(id integer,val varchar(4));

Table created.

SQL> insert into tab01 values(1,'0001');

1 row created.

SQL> insert into tab01 values(2,'0002');       

1 row created.

SQL> insert into tab01 values(3,'0003');

1 row created.

SQL> insert into tab01 values(4,'0004');

1 row created.

SQL> select rowid, tab01.* from tab01;

ROWID                      ID VAL
------------------ ---------- ----
AAAVVLAAEAAAACvAAA          1 0001
AAAVVLAAEAAAACvAAB          2 0002
AAAVVLAAEAAAACvAAC          3 0003
AAAVVLAAEAAAACvAAD          4 0004

SQL>
******************************************************

[oracle@localhost ~]$ cat test.sql
select dbms_rowid.rowid_object(rowid) object_id,
       dbms_rowid.rowid_relative_fno(rowid) file_id,
       dbms_rowid.rowid_block_number(rowid) block_id,
       dbms_rowid.rowid_row_number(rowid) num ,id,val from tab01;
[oracle@localhost ~]$

SQL> @test.sql;

 OBJECT_ID    FILE_ID   BLOCK_ID        NUM         ID VAL
---------- ---------- ---------- ---------- ---------- ----
     87371          4        175          0          1 0001
     87371          4        175          1          2 0002
     87371          4        175          2          3 0003
     87371          4        175          3          4 0004

SQL>

[oracle@localhost ~]$ cat test02.sql
select rowid,
     substr(rowid,1,6) "object",
     substr(rowid,7,3) "file",
     substr(rowid,10,6) "block",
     substr(rowid,16,3) "row",  
     id,val from tab01;

[oracle@localhost ~]$

SQL> @test02.sql;

ROWID              object fil block  row         ID VAL
------------------ ------ --- ------ --- ---------- ----
AAAVVLAAEAAAACvAAA AAAVVL AAE AAAACv AAA          1 0001
AAAVVLAAEAAAACvAAB AAAVVL AAE AAAACv AAB          2 0002
AAAVVLAAEAAAACvAAC AAAVVL AAE AAAACv AAC          3 0003
AAAVVLAAEAAAACvAAD AAAVVL AAE AAAACv AAD          4 0004

SQL>

******************************************************

如果，把数据库进行冷备份，然后恢复会如何？

SQL> @test02.sql;

ROWID              object fil block  row         ID VAL
------------------ ------ --- ------ --- ---------- ----
AAAVVLAAEAAAACvAAA AAAVVL AAE AAAACv AAA          1 0001
AAAVVLAAEAAAACvAAB AAAVVL AAE AAAACv AAB          2 0002
AAAVVLAAEAAAACvAAC AAAVVL AAE AAAACv AAC          3 0003
AAAVVLAAEAAAACvAAD AAAVVL AAE AAAACv AAD          4 0004

SQL>

SQL> @test.sql;

 OBJECT_ID    FILE_ID   BLOCK_ID        NUM         ID VAL
---------- ---------- ---------- ---------- ---------- ----
     87371          4        175          0          1 0001
     87371          4        175          1          2 0002
     87371          4        175          2          3 0003
     87371          4        175          3          4 0004

SQL>

完全没有变化。

现在重新作表，看导出导入到其他机器上状况会如何：

[oracle@o_target ~]$ sqlplus gao/gao

SQL*Plus: Release 11.2.0.1.0 Production on Fri Apr 4 09:42:57 2014

Copyright (c) 1982, 2009, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> create table gaotab(id integer,val varchar(3));

Table created.

SQL> insert into gaotab values(4,'004');

1 row created.

SQL> insert into gaotab values(1,'001');

1 row created.

SQL> insert into gaotab values(3,'003');

1 row created.

SQL> insert into gaotab values(2,'002');

1 row created.

SQL> commit;

Commit complete.

SQL>