1.数据库对象号(1-6)
2.行所在数据文件号（7-9）
3.行所在数据文件中的块号（10-15）
4.行所在数据块中的位置（16-18）
|
XXXXXX |
XXX |
XXXXXX |
XXX |
|
Data Object ID |
Relative File No |
Block Number |
Row Number(Slot) |
SQL> select rowid from rowid_example;
ROWID
------------------
AAANdqAABAAAPFyAAA
|
AAANdq |
AAB |
AAAPFy |
AAA |
|
Data Object ID |
Relative File No |
Block Number |
Row Number(Slot) |
|
Decimal Sequence |
Base-64 Representation |
|
0 – 25 |
‘A’ – ‘ Z’ (A through Z) |
|
26 – 51 |
‘a’ – ‘z’ (a through z) |
|
52 – 61 |
‘0’ – ‘9’ (0 through 9) |
|
62 |
‘+’ |
|
63 |
‘/’ |
2. Convert the binary representation to decimal value to
(000000000000000000001101011101101010) -> (55146) => (Binary) -> (Decimal)
SQL>select data_object_id from dba_objects where object_name='ROWID_EXAMPLE';
DATA_OBJECT_ID
--------------
55146
3. Similarly we can convert the Relative File Number, Block Number and the Row Slot (Number).
Read the conversion below as => (Base-64) -> (Binary) -> (Decimal)
(AAB) -> (000000 000000 000001) -> (1)
(AAAPFy) -> (000000 000000 000000 001111 000101 110010) -> (61810)
(AAA) -> (000000 000000 000000) -> (0)
Using the Relative File Number and the Block Number in the following query we can get the Object Name.
SQL> select segment_name, segment_type, owner from dba_extents
where file_id=1 and 61810 between block_id and block_id + blocks - 1;
SEGMENT_NAME SEGMENT_TYPE OWNER
-------------------------- ------------------ --------------
ROWID_EXAMPLE TABLE SYS
在oracle中可以通过dbms_rowid包把rowid转换成易懂的内容
1.查看行的文件号
select ROWID,DBMS_ROWID.ROWID_RELATIVE_FNO(rowid) file_id from emp;
ROWID FILE_ID
------------------ ----------
AAAR3sAAEAAAACXAAA 4
AAAR3sAAEAAAACXAAB 4
2.查看行的数据块号
select ROWID,DBMS_ROWID.ROWID_BLOCK_NUMBER(rowid)block_id from emp;
ROWID BLOCK_ID
------------------ ----------
AAAR3sAAEAAAACXAAA 151
AAAR3sAAEAAAACXAAB 151
3.查看行号
select ROWID,DBMS_ROWID.ROWID_ROW_NUMBER(rowid)row_number from emp;
ROWID ROW_NUMBER
------------------ ----------
AAAR3sAAEAAAACXAAA 0
AAAR3sAAEAAAACXAAB 1
4.看对象号
select ROWID,DBMS_ROWID.ROWID_OBJECT(rowid)object_id from emp;
ROWID OBJECT_ID
------------------ ----------
AAAR3sAAEAAAACXAAA 73196
AAAR3sAAEAAAACXAAB 73196
select object_id,object_name from user_objects where object_name='EMP'
OBJECT_ID OBJECT_NAME
---------- ------------------------------
73196 EMP
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