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skip lock

原创 网络安全 作者:playwawa 时间:2005-09-09 17:41:16 0 删除 编辑
有人问到这样的问题:如果一个用户对记录加锁,如何使其他用户看不到这条记录。
此前并未注意到这样一个用法(需要8.1.7.4.16以上的版本支持):[@more@]

[oracle@jumper oracle]$ sqlplus scott/tiger

SQL*Plus: Release 9.2.0.4.0 - Production on Fri Mar 4 11:59:46 2005

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.


Connected to:
Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production
With the Partitioning option
JServer Release 9.2.0.4.0 - Production

SQL> select * from dept;

DEPTNO DNAME LOC
---------- -------------- -------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON
33 ORACLE beijing
35 Oracle Beijing
36 Oracle Beijing
37 Oracle Beijing

8 rows selected.

SQL> select * from dept where deptno =10 for update;

DEPTNO DNAME LOC
---------- -------------- -------------
10 ACCOUNTING NEW YORK

SQL> !
[oracle@jumper oracle]$ sqlplus scott/tiger

SQL*Plus: Release 9.2.0.4.0 - Production on Fri Mar 4 12:00:14 2005

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.


Connected to:
Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production
With the Partitioning option
JServer Release 9.2.0.4.0 - Production

SQL> select * from dept for update skip locked;

DEPTNO DNAME LOC
---------- -------------- -------------
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON
33 ORACLE beijing
35 Oracle Beijing
36 Oracle Beijing
37 Oracle Beijing

7 rows selected.

SQL>

存此备忘。

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