mysql> create table Teachher(? ? -> id int(4) primary key not null unique auto_increment,? ? -> num int(10) not null unique,? ? -> name varchar(20) not null,? ? -> sex varchar(4) not null,? ? -> birthday datetime,? ? -> address varchar(59)? ? -> );Query OK, 0 rows affected (0.67 sec)mysql> desc Teachher;+----------+-------------+------+-----+---------+----------------+| Field ? ?| Type ? ? ? ?| Null | Key | Default | Extra ? ? ? ? ?|+----------+-------------+------+-----+---------+----------------+| id ? ? ? | int(4) ? ? ?| NO ? | PRI | NULL ? ?| auto_increment || num ? ? ?| int(10) ? ? | NO ? | UNI | NULL ? ?| ? ? ? ? ? ? ? ?|| name ? ? | varchar(20) | NO ? | ? ? | NULL ? ?| ? ? ? ? ? ? ? ?|| sex ? ? ?| varchar(4) ?| NO ? | ? ? | NULL ? ?| ? ? ? ? ? ? ? ?|| birthday | datetime ? ?| YES ?| ? ? | NULL ? ?| ? ? ? ? ? ? ? ?|| address ?| varchar(59) | YES ?| ? ? | NULL ? ?| ? ? ? ? ? ? ? ?|+----------+-------------+------+-----+---------+----------------+6 rows in set (0.01 sec)mysql> insert into Teachher(num)? ? -> values('2513');ERROR 1364 (HY000): Field 'name' doesn't have a default valuemysql> insert into Teachher(num)? ? -> values(2513);ERROR 1364 (HY000): Field 'name' doesn't have a default value