Oracle 10gr2:执行的日期是在上午9点到下午5点之间？

我想强制执行输入的日期 - 时间是在上午9点到下午5点之间.如何使用ORACLE CHECK约束强制执行此操作？

SQL> ed
Wrote file afiedt.buf

  1  create table date_check (
  2  dt date check( to_number( to_char( dt, 'HH24' ) ) between 9 and 16 )
  3* )
SQL> /

Table created.

SQL> ed
Wrote file afiedt.buf

  1* insert into date_check values( to_date( '01/01/2008 08:30', 'DD/MM/YYYY HH2
4:MI' ) )
SQL> /
insert into date_check values( to_date( '01/01/2008 08:30', 'DD/MM/YYYY HH24:MI'
 ) )
*
ERROR at line 1:
ORA-02290: check constraint (SCOTT.SYS_C006170) violated


SQL> ed
Wrote file afiedt.buf

  1* insert into date_check values( to_date( '01/01/2008 10:30', 'DD/MM/YYYY HH2
4:MI' ) )
SQL> /

1 row created.

SQL> ed
Wrote file afiedt.buf

  1* insert into date_check values( to_date( '01/01/2008 17:30', 'DD/MM/YYYY HH2
4:MI' ) )
SQL> /

insert into date_check values( to_date( '01/01/2008 17:30', 'DD/MM/YYYY HH24:MI'
 ) )
*
ERROR at line 1:
ORA-02290: check constraint (SCOTT.SYS_C006170) violated