dbms_rowid.rowid_relative_fno：定位该数据行所在的数据文件
dbms_rowid.rowid_block_number：定位该数据行在数据文件的第多少个块
dbms_rowid.rowid_row_number：定位该数据行在数据块的第多少行
下面举例进行查看：
SCOTT@ORCL>desc emp
Name Null Type
----------------------------------------- -------- ----------------------------
EMPNO NOT NULL NUMBER(4)
ENAME VARCHAR2(10)
JOB VARCHAR2(9)
MGR NUMBER(4)
HIREDATE DATE
SAL NUMBER(7,2)
COMM NUMBER(7,2)
DEPTNO NUMBER(2)
SCOTT@ORCL>col location for a20
SCOTT@ORCL>select empno,rowid,dbms_rowid.rowid_relative_fno(rowid) || '_' ||dbms_rowid.rowid_block_number(rowid) || '_' || dbms_rowid.rowid_row_number(rowid) location
2 from emp;
EMPNO ROWID LOCATION
---------- ------------------ --------------------
7369 AAAMfMAAEAAAAAgAAA 4_32_0
7499 AAAMfMAAEAAAAAgAAB 4_32_1
7521 AAAMfMAAEAAAAAgAAC 4_32_2
7566 AAAMfMAAEAAAAAgAAD 4_32_3
7654 AAAMfMAAEAAAAAgAAE 4_32_4
7698 AAAMfMAAEAAAAAgAAF 4_32_5
7782 AAAMfMAAEAAAAAgAAG 4_32_6
7788 AAAMfMAAEAAAAAgAAH 4_32_7
7839 AAAMfMAAEAAAAAgAAI 4_32_8
7844 AAAMfMAAEAAAAAgAAJ 4_32_9
7876 AAAMfMAAEAAAAAgAAK 4_32_10
EMPNO ROWID LOCATION
---------- ------------------ --------------------
7900 AAAMfMAAEAAAAAgAAL 4_32_11
7902 AAAMfMAAEAAAAAgAAM 4_32_12
7934 AAAMfMAAEAAAAAgAAN 4_32_13
14 rows selected.
拿第一行数据进行说明该行的ROWID伪列的值为 AAAMfMAAEAAAAAgAAA，可以通过ROWID包通过这个ROWID伪列转换出来的值为4_32_0，代表该行在数据文件4的第32个数据块的第0行。