Oracle 锁机制

Oracle多粒度封锁机制研究：
http://www.itpub.net/viewthread.php?tid=202492&highlight=%CB%F8
我对ORACLE数据锁的一点体会：
http://www.itpub.net/viewthread.php?tid=270059&highlight=%CB%F8


在Oracle中如何实现读锁：
http://www.itpub.net/viewthread.php?tid=995175&highlight=%CB%F8




给表加锁：

lock table tablename in modename mode [nowait]

关于SELECT FOR UPDATE：
语法：

SELECT ... FOR UPDATE [OF column_list][WAIT n|NOWAIT][SKIP LOCKED]; 

Select For Update会产生2个锁：
http://blog.csdn.net/java2000_net/archive/2009/01/06/3719481.aspx
Oracle 的for update行锁2：
http://fhd001.iteye.com/blog/502733
对oracle锁的一点见解：
http://blog.csdn.net/flying_hawk/archive/2009/01/14/3773380.aspx

Oracle/PLSQL: SELECT FOR UPDATE Statement：
http://www.techonthenet.com/oracle/cursors/for_update.php
Oracle/PLSQL: WHERE CURRENT OF Statement：
http://www.techonthenet.com/oracle/cursors/current_of.php

Note：select for update的select列表中不允许使用GROUP BY, DISTINCT, UNION, INTERSECT, or MINUS等聚合函数，否则会报ORA-01786：
http://ora-01786.ora-code.com/

引用

ORA-01786:FOR UPDATE of this query expression is not allowed
Cause:An attempt was made to use a FOR UPDATE clause on the result of a set expression involving GROUP BY, DISTINCT, UNION, INTERSECT, or MINUS.
Action:Check the syntax, remove the FOR UPDATE clause, and retry the statement.