改善Defaults

SQL> create table t_test1(id number,phone varchar2(20) default null);

Table created.

SQL> CREATE SEQUENCE seq_test start with 1 increment by 1;

SQL> select seq_test.nextval from dual;

SQL> insert into t_test1(phone) values ('1666');

1 row created.

SQL> select * from t_test1

2 ;

SQL> alter table t_test1 add a2 varchar2(20) default null;

Table altered.

     本文轉自whshurk 51CTO部落格，原文連結：http://blog.51cto.com/shurk/2057027，如需轉載請自行聯系原作者