oracle 插入date

插入几种日期格式的方法:

1.

insert into authors(author_id,first_name,last_name,birthdate)  values  (25,'David','Sell',to_date('22-06-2005','DD-MM-YYYY')) 

这种情况可以正常insert

2.

中文系统下： 
insert into authors(author_id,first_name,last_name,birthdate)  values (27,'David','Sell',to_date('14-6月-2008','DD-MON-YYYY')); 

英文系统下： 
insert into authors(author_id,first_name,last_name,birthdate) values (27,'David','Sell',to_date('14-JAN-2008','DD-MON-YYYY')); 

3.

alter session set nls_date_language='american'; 

insert into authors(author_id,first_name,last_name,birthdate) values (27,'David','Sell',to_date('14-JAN-2008','DD-MON-YYYY'));