日期的存储格式：
22-FEB-81: 77 b5 02 16 01 01 01
19-APR-87: 77 bb 04 13 01 01 01
bbed中把WARD 中的22-FEB-81改为19-APR-87
BBED> x /r
rowdata[443] @8064
------------
flag@8064: 0x2c (KDRHFL, KDRHFF, KDRHFH)
lock@8065: 0x00
cols@8066: 8
col 0[3] @8067: 0xc2 0x4c 0x16
col 1[4] @8071: 0x57 0x41 0x52 0x44
col 2[8] @8076: 0x53 0x41 0x4c 0x45 0x53 0x4d 0x41 0x4e
col 3[3] @8085: 0xc2 0x4d 0x63
col 4[7] @8089: 0x77 0xb5 0x02 0x16 0x01 0x01 0x01
col 5[3] @8097: 0xc2 0x0d 0x33
col 6[2] @8101: 0xc2 0x09
col 7[2] @8104: 0xc1 0x1f
设置偏移量到日期字段的起始位置：
BBED> dump /v offset 8089 count 64
File: /opt/oracle/oradata/orcl/users01.dbf (4)
Block: 396 Offsets: 8089 to 8152 Dba:0x0100018c
-------------------------------------------------------
0777b502 16010101 03c20d33 02c20902 l .w.........3....
c11f2c00 0803c24b 6405414c 4c454e08 l ..,....Kd.ALLEN.
53414c45 534d414e 03c24d63 0777b502 l SALESMAN..Mc.w..
14010101 02c21102 c20402c1 1f2c0008 l .............,..
再次偏移：8089+1=8090
BBED> dump /v offset 8090 count 64
File: /opt/oracle/oradata/orcl/users01.dbf (4)
Block: 396 Offsets: 8090 to 8153 Dba:0x0100018c
-------------------------------------------------------
77b50216 01010103 c20d3302 c20902c1 l w.........3.....
1f2c0008 03c24b64 05414c4c 454e0853 l .,....Kd.ALLEN.S
414c4553 4d414e03 c24d6307 77b50214 l ALESMAN..Mc.w...
01010102 c21102c2 0402c11f 2c000803 l ............,...
修改日期数据
一次只能修改4个字节大小以内的，否则报错。
BBED> modify /x 77bb0413010101
BBED-00209: invalid number (0x786e0602140c1f)
分开修改
BBED> modify /x 77bb0413
File: /opt/oracle/oradata/orcl/users01.dbf (4)
Block: 396 Offsets: 8090 to 8153 Dba:0x0100018c
------------------------------------------------------------------------
77bb0413 01010103 c20d3302 c20902c1 1f2c0008 03c24b64 05414c4c 454e0853
414c4553 4d414e03 c24d6307 77b50214 01010102 c21102c2 0402c11f 2c000803
BBED> set offset 8094
OFFSET 8094
BBED> dump /v offset 8094
File: /opt/oracle/oradata/orcl/users01.dbf (4)
Block: 396 Offsets: 8094 to 8157 Dba:0x0100018c
-------------------------------------------------------
01010103 c20d3302 c20902c1 1f2c0008 l ......3......,..
03c24b64 05414c4c 454e0853 414c4553 l ..Kd.ALLEN.SALES
4d414e03 c24d6307 77b50214 01010102 l MAN..Mc.w.......
c21102c2 0402c11f 2c000803 c24a4605 l ........,....JF.
应用校验和。
BBED> sum dba 4,396 apply
Check value for File 4, Block 396:
current = 0x23cb, required = 0x23cb
BBED> x /rnccntnnn --查看，结果已修改
rowdata[443] @8064
------------
flag@8064: 0x2c (KDRHFL, KDRHFF, KDRHFH)
lock@8065: 0x00
cols@8066: 8
col 0[3] @8067: 7521
col 1[4] @8071: WARD
col 2[8] @8076: SALESMAN
col 3[3] @8085: 7698
col 4[7] @8089: 19-APR-87
col 5[3] @8097: 1250
col 6[2] @8101: 800
col 7[2] @8104: 30
sqlplus中测试查询：
SQL> select * from yangobj;
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- --------------- ---------- ---------- ------------------ ---------- ---------- ----------
7369 SMITH CLERK 7902 17-DEC-80 800 20
7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30
7521 WARD SALESMAN 7698 19-APR-87 1250 800 30