Oracle rowid

SYS@ prod>select rowid from scott.emp;ROWID
------------------
AAASPXAAEAAAACVAAA
AAASPXAAEAAAACVAAB
AAASPXAAEAAAACVAAC
AAASPXAAEAAAACVAAD
AAASPXAAEAAAACVAAE?

ROWID的格式如下：

數據對象編號 文件編號 塊編號 行編號
AAASPX AAE AAAACV AAA

我們可以看出，從上面的rowid可以得知：
AAASPX?是數據對象編號 （data_object)
AAE?是數據文件編號 (datafile)
AAAACV?是塊編號 (block)
AAA 是行編號 (row)

怎么依據這些編號得到具體的十進制的編碼值呢

這里需要明白rowid的是基于64位編碼的18個字符顯示（數據對象編號(6) +文件編號(3) +塊編號(6)+ 行編號 (3)=18位），其中
A-Z <==> 0 - 25 (26)
a-z <==> 26 - 51 (26)
0-9 <==> 52 - 61 (10)
+/ <==> 62 - 63 (2)

共64位，明白這個后，就可以計算出10進制的編碼值，計算公式如下：
d * (b ^ p)
其中：b就是基數，這里就是64，p就是從右到左，以0開始的位置數
比如：上面的例子
對象號AAASPX?,具體的計算應該是:
0*(64^5)=5；0*(64^4)=0；0*(64^3)=0；18*(64^2)=73728；15*(64^1)=960；23*(64^0)=23；

對象號就是73728+960+23=74711

剛才提到的是rowid的顯示方式：基于64位編碼的18個字符顯示，其實rowid的存儲方式是：10 個字節即80位存儲，其中數據對象編號需要32 位，相關文件編號需要10 位，塊編號需要22，位行編號需要16 位，由此，我們可以得出：
32bit的object number，每個數據庫最多有4G個對象
10bit的file number，每個對象最多有1022個文件（2個文件預留）
22bit的block number，每個文件最多有4M個BLOCK
16bit的row number，每個BLOCK最多有64K個ROWS

2. rowid相關的有用的sql

通過dbms_rowid這個包，可以直接的得到具體的rowid包含的信息：

SYS@ prod>select dbms_rowid.rowid_object(rowid) object_id, dbms_rowid.rowid_relative_fno(rowid) file_id,2  dbms_rowid.rowid_block_number(rowid) block_id ,dbms_rowid.rowid_row_number(rowid) num from scott.emp 3  where rownum<5;OBJECT_ID    FILE_ID   BLOCK_ID        NUM
---------- ---------- ---------- ----------74711          4        149          0
     74711          4        149          174711          4        149          274711          4        149          3?

一些使用ROWID的函數
ROWIDTOCHAR(rowid) ：將ROWID轉換成STRING
CHARTOROWID('rowid_string') ：將STRING轉換成ROWID

如果沒有dbms包的權限可以用下面的方法

select
(case when to_number(utl_raw.cast_to_raw(substr(rowid,1,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,1,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,1,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,1,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,1,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,1,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,1,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,1,1)),'xxx') = 47 then 63 end)*power(64,5)+
(case when to_number(utl_raw.cast_to_raw(substr(rowid,2,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,2,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,2,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,2,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,2,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,2,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,2,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,2,1)),'xxx') = 47 then 63 end)*power(64,4)+
(case when to_number(utl_raw.cast_to_raw(substr(rowid,3,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,3,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,3,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,3,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,3,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,3,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,3,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,3,1)),'xxx') = 47 then 63 end)*power(64,3)+
(case when to_number(utl_raw.cast_to_raw(substr(rowid,4,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,4,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,4,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,4,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,4,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,4,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,4,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,4,1)),'xxx') = 47 then 63 end)*power(64,2)+
(case when to_number(utl_raw.cast_to_raw(substr(rowid,5,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,5,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,5,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,5,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,5,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,5,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,5,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,5,1)),'xxx') = 47 then 63 end)*power(64,1)+
(case when to_number(utl_raw.cast_to_raw(substr(rowid,6,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,6,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,6,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,6,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,6,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,6,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,6,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,6,1)),'xxx') = 47 then 63 end)*power(64,0) as object_cd,
(case when to_number(utl_raw.cast_to_raw(substr(rowid,7,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,7,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,7,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,7,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,7,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,7,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,7,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,7,1)),'xxx') = 47 then 63 end)*power(64,2)+
(case when to_number(utl_raw.cast_to_raw(substr(rowid,8,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,8,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,8,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,8,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,8,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,8,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,8,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,8,1)),'xxx') = 47 then 63 end)*power(64,1)+
(case when to_number(utl_raw.cast_to_raw(substr(rowid,9,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,9,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,9,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,9,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,9,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,9,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,9,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,9,1)),'xxx') = 47 then 63 end)*power(64,0) as file_no,
(case when to_number(utl_raw.cast_to_raw(substr(rowid,10,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,10,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,10,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,10,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,10,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,10,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,10,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,10,1)),'xxx') = 47 then 63 end)*power(64,5)+
(case when to_number(utl_raw.cast_to_raw(substr(rowid,11,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,11,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,11,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,11,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,11,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,11,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,11,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,11,1)),'xxx') = 47 then 63 end)*power(64,4)+
(case when to_number(utl_raw.cast_to_raw(substr(rowid,12,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,12,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,12,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,12,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,12,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,12,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,12,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,12,1)),'xxx') = 47 then 63 end)*power(64,3)+
(case when to_number(utl_raw.cast_to_raw(substr(rowid,13,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,13,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,13,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,13,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,13,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,13,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,13,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,13,1)),'xxx') = 47 then 63 end)*power(64,2)+
(case when to_number(utl_raw.cast_to_raw(substr(rowid,14,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,14,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,14,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,14,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,14,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,14,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,14,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,14,1)),'xxx') = 47 then 63 end)*power(64,1)+
(case when to_number(utl_raw.cast_to_raw(substr(rowid,15,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,15,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,15,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,15,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,15,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,15,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,15,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,15,1)),'xxx') = 47 then 63 end)*power(64,0) as block_no,
(case when to_number(utl_raw.cast_to_raw(substr(rowid,16,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,16,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,16,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,16,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,16,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,16,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,16,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,16,1)),'xxx') = 47 then 63 end)*power(64,2)+
(case when to_number(utl_raw.cast_to_raw(substr(rowid,17,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,17,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,17,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,17,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,17,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,17,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,17,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,17,1)),'xxx') = 47 then 63 end)*power(64,1)+
(case when to_number(utl_raw.cast_to_raw(substr(rowid,18,1)),'xxx') between 48 and 58 then to_number(utl_raw.cast_to_raw(substr(rowid,18,1)),'xxx')+4 when to_number(utl_raw.cast_to_raw(substr(rowid,18,1)),'xxx') between 65 and 91 then to_number(utl_raw.cast_to_raw(substr(rowid,18,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,18,1)),'xxx') between 97 and 123 then to_number(utl_raw.cast_to_raw(substr(rowid,18,1)),'xxx')-65 when to_number(utl_raw.cast_to_raw(substr(rowid,18,1)),'xxx') = 43 then 62 when to_number(utl_raw.cast_to_raw(substr(rowid,18,1)),'xxx') = 47 then 63 end)*power(64,0) as row_no
from scott.emp;

?