创建表时添加约束

查询表中搞得约束信息：show keys from 表名;

示例：创建depts表包含department_id该列为主键且自动增长，department_name列不允许重复，location_id列不允许含有空值；

create table depts (department_id int primary key auto_increment,department_name varchar(30) unique,location_id int not null);