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oracle rowid 的使用方法

1.创建一临时表
create table test_rowid (id number, row_id rowid);
2.插入一行记录
insert into test_rowid values(1,null);
3.修改刚插入的记录
update test_rowid set row_id = rowid where id = 1;
4.查看rowid
rowid,row_id from test_rowid;
返回结果为:
rowid                                                      row_id
AAAO0DAAJAAAAMYAAA               AAAO0DAAJAAAAMYAAA

Oracle的物理扩展ROWID有18位,每位采用64位编码,分别用A~Z、a~z、0~9、+、/共64个字符表示。A表示0,B表示1,……Z表示25,a表示26,……z表示51,0表示52,……,9表示61,+表示62,/表示63。

ROWID具体划分可以分为4部分。

(1).OOOOOO:前6位表示DATA OBJECT NUMBER,将起转化位数字后匹配DBA_OBJECTS中的DATA_OBJECT_ID,可以确定表信息。

如上面例子中的DATA OBJECT NUMBER是AAAO0D,转化位数字是14×64×64 +52×64 + 3。
输入以下查询:
select owner, object_name from dba_objects where data_object_id = 14*64*64 + 52*64 + 3;
返回:
OWNER    OBJECT_NAME
WG             TEST_ROWID
(2)FFF:第7到9位表示相对表空间的数据文件号。
上面的例子中是AAJ,表示数据文件9。
输入以下查询:
(3).BBBBBB:第10到15位表示这条记录在数据文件中的第几个BLOCK中。

上面的例子是AAAAMY,转化位数字是12×64+24,表示这条记录在数据文件中的第792个BLOCK。

(4).RRR:最后3位表示这条记录是BLOCK中的第几条记录。

上面的例子是AAA,表示第0条记录(总是从0开始计数)。

四.参考资料

1.oracle rowid
2.Oracle基本数据类型存储格式浅析(四)——ROWID类型(一)
3.oracle数据文件为什么存在 Rfile# and file#

SQL> CREATE TABLE EMP (EMPNO NUMBER(4) NOT NULL,
  2                    ENAME VARCHAR2(10),
  3                    JOB VARCHAR2(9),
  4                    MGR NUMBER(4),
  5                    HIREDATE DATE,
  6                    SAL NUMBER(7, 2),
  7                    COMM NUMBER(7, 2),
  8                    DEPTNO NUMBER(2));

Table created.

SQL>
SQL> INSERT INTO EMP VALUES (7369, 'SMITH', 'CLERK',    7902, TO_DATE('17-DEC-1980', 'DD-MON-YYYY'), 800, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7499, 'ALLEN', 'SALESMAN', 7698, TO_DATE('20-FEB-1981', 'DD-MON-YYYY'), 1600, 300, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7521, 'WARD',  'SALESMAN', 7698, TO_DATE('22-FEB-1981', 'DD-MON-YYYY'), 1250, 500, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7566, 'JONES', 'MANAGER',  7839, TO_DATE('2-APR-1981',  'DD-MON-YYYY'), 2975, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7654, 'MARTIN', 'SALESMAN', 7698,TO_DATE('28-SEP-1981', 'DD-MON-YYYY'), 1250, 1400, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7698, 'BLAKE', 'MANAGER', 7839,TO_DATE('1-MAY-1981', 'DD-MON-YYYY'), 2850, NULL, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7782, 'CLARK', 'MANAGER', 7839,TO_DATE('9-JUN-1981', 'DD-MON-YYYY'), 2450, NULL, 10);

1 row created.

SQL> INSERT INTO EMP VALUES (7788, 'SCOTT', 'ANALYST', 7566,TO_DATE('09-DEC-1982', 'DD-MON-YYYY'), 3000, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7839, 'KING', 'PRESIDENT', NULL,TO_DATE('17-NOV-1981', 'DD-MON-YYYY'), 5000, NULL, 10);

1 row created.

SQL> INSERT INTO EMP VALUES (7844, 'TURNER', 'SALESMAN', 7698,TO_DATE('8-SEP-1981', 'DD-MON-YYYY'), 1500, 0, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7876, 'ADAMS', 'CLERK', 7788,TO_DATE('12-JAN-1983', 'DD-MON-YYYY'), 1100, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7900, 'JAMES', 'CLERK', 7698,TO_DATE('3-DEC-1981', 'DD-MON-YYYY'), 950, NULL, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7902, 'FORD', 'ANALYST', 7566,TO_DATE('3-DEC-1981', 'DD-MON-YYYY'), 3000, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7934, 'MILLER', 'CLERK', 7782,TO_DATE('23-JAN-1982', 'DD-MON-YYYY'), 1300, NULL, 10);

1 row created.

SQL>
SQL> CREATE TABLE DEPT (DEPTNO NUMBER(2),DNAME VARCHAR2(14),LOC VARCHAR2(13) );

Table created.

SQL>
SQL> INSERT INTO DEPT VALUES (10, 'ACCOUNTING', 'NEW YORK');

1 row created.

SQL> INSERT INTO DEPT VALUES (20, 'RESEARCH', 'DALLAS');

1 row created.

SQL> INSERT INTO DEPT VALUES (30, 'SALES', 'CHICAGO');

1 row created.

SQL> INSERT INTO DEPT VALUES (40, 'OPERATIONS', 'BOSTON');

1 row created.

SQL>
SQL> select rowid from emp
  2  intersect
  3  select rowid from dept;


实例

SQL> select * from Employee
  2  /

ID   FIRST_NAME LAST_NAME  START_DAT END_DATE      SALARY CITY       DESCRIPTION
---- ---------- ---------- --------- --------- ---------- ---------- ---------------
01   Jason      Martin     25-JUL-96 25-JUL-06    1234.56 Toronto    Programmer
02   Alison     Mathews    21-MAR-76 21-FEB-86    6661.78 Vancouver  Tester
03   James      Smith      12-DEC-78 15-MAR-90    6544.78 Vancouver  Tester
04   Celia      Rice       24-OCT-82 21-APR-99    2344.78 Vancouver  Manager
05   Robert     Black      15-JAN-84 08-AUG-98    2334.78 Vancouver  Tester
06   Linda      Green      30-JUL-87 04-JAN-96    4322.78 New York   Tester
07   David      Larry      31-DEC-90 12-FEB-98    7897.78 New York   Manager
08   James      Cat        17-SEP-96 15-APR-02    1232.78 Vancouver  Tester

8 rows selected.

SQL>
SQL>
SQL> SELECT ROWID, id FROM employee
  2  /

ROWID              ID
------------------ ----
AAAFx7AABAAAKjCAAA 01
AAAFx7AABAAAKjCAAB 02
AAAFx7AABAAAKjCAAC 03
AAAFx7AABAAAKjCAAD 04
AAAFx7AABAAAKjCAAE 05
AAAFx7AABAAAKjCAAF 06
AAAFx7AABAAAKjCAAG 07
AAAFx7AABAAAKjCAAH 08

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