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delete未提交rollback是否会改变行号

2016-06-22 18:54 148 查看
今天做个试验,delete未提交rollback是否会改变行号?

创建测试表:
create table dxmy (id number,name varchar2(100));

插入数据
insert into dxmy values(1,'dxmy');
insert into dxmy values(2,'dxmy');
insert into dxmy values(3,'dxmy');
insert into dxmy values(4,'dxmy');
commit;

查看行号
SQL> select dbms_rowid.rowid_relative_fno(rowid) fno,
  2         dbms_rowid.rowid_block_number(rowid) block_id,
  3         dbms_rowid.rowid_row_number(rowid) row_id,
  4         id
  5    from dxmy;
 
       FNO   BLOCK_ID     ROW_ID         ID
---------- ---------- ---------- ----------
         4        462          0          1
         4        462          1          2
         4        462          2          3
         4        462          3          4

delete,但是不提交:
SQL> delete dxmy where id = 1;
 
1 row deleted
 
SQL>
SQL> select dbms_rowid.rowid_relative_fno(rowid) fno,
  2         dbms_rowid.rowid_block_number(rowid) block_id,
  3         dbms_rowid.rowid_row_number(rowid) row_id,
  4         id
  5    from dxmy;
 
       FNO   BLOCK_ID     ROW_ID         ID
---------- ---------- ---------- ----------
         4        462          1          2
         4        462          2          3
         4        462          3          4

rollback:
SQL> rollback;
 
Rollback complete

SQL> select dbms_rowid.rowid_relative_fno(rowid) fno,
  2         dbms_rowid.rowid_block_number(rowid) block_id,
  3         dbms_rowid.rowid_row_number(rowid) row_id,
  4         id
  5    from dxmy;
 
       FNO   BLOCK_ID     ROW_ID         ID
---------- ---------- ---------- ----------
         4        462          0          1
         4        462          1          2
         4        462          2          3
         4        462          3          4

行号未改变。

那如果delete之后,我提交了,然后重新插入呢?
SQL> delete dxmy where id = 1;
 
1 row deleted
 
SQL> commit;
 
Commit complete
SQL> insert into dxmy values(1,'dxmy');
 
1 row inserted
 
SQL> commit;
 
Commit complete

SQL> select dbms_rowid.rowid_relative_fno(rowid) fno,
  2         dbms_rowid.rowid_block_number(rowid) block_id,
  3         dbms_rowid.rowid_row_number(rowid) row_id,
  4         id
  5    from dxmy;
 
       FNO   BLOCK_ID     ROW_ID         ID
---------- ---------- ---------- ----------
         4        462          1          2
         4        462          2          3
         4        462          3          4
         4        463          0          1

<pre name="code" class="html">SQL> delete dxmy where id = 1;
 
1 row deleted
 
SQL> commit;
 
Commit complete


SQL> insert into dxmy values(1,'dxmy2');

1 row inserted

SQL> commit;

Commit complete

SQL>

SQL> select dbms_rowid.rowid_relative_fno(rowid) fno,

2 dbms_rowid.rowid_block_number(rowid) block_id,

3 dbms_rowid.rowid_row_number(rowid) row_id,

4 id

5 from dxmy;

FNO BLOCK_ID ROW_ID ID

---------- ---------- ---------- ----------

4 462 1 2

4 462 2 3

4 462 3 4

4 463 1 1

然后就发现:

1.delete未提交即rollback不会改变行号

2.delete提交后插入数据,可能会改变行号,但是也有可能不改变,但行的位置肯定会改变。


                                            
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