原文: http://blog.itpub.net/29371470/viewspace-1081319/ [oracle@rhel ~]$ sqlplus / as sysdba SQL*Plus: Release 10.2.0.5.0 - Production on Sat Feb 8 12:51:15 2014 Copyright (c) 1982, 2010, Oracle.  All Rights Reserved. Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - Production With the Partitioning, OLAP, Data Mining and Real Application Testing options SQL> create user lsq identified by lsq; User created. SQL> grant connect, resource to lsq; Grant succeeded. SQL> conn lsq/lsq Connected. SQL> disc Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - Production With the Partitioning, OLAP, Data Mining and Real Application Testing options SQL> conn / as sysdba Connected. SQL> CREATE OR REPLACE TRIGGER limit_connection   2       AFTER LOGON ON DATABASE   3    BEGIN   4       IF USER = 'LSQ' THEN   5          IF to_number(TO_CHAR (SYSDATE, 'hh24')) BETWEEN 8 AND 22   6          THEN   7             RAISE_APPLICATION_ERROR(-20998,' Dear user '||USER||'! You can''t login between 08 and 22');   8          END IF;   9       END IF; 10   END limit_connection; 11   / Trigger created. SQL> select to_char(sysdate,'hh24') from dual; TO -- 12 SQL> conn lsq/lsq ERROR: ORA-00604: error occurred at recursive SQL level 1 ORA-20998:  Dear user LSQ! You can't login between 08 and 22 ORA-06512: at line 5 Warning: You are no longer connected to ORACLE.