摘要： create database ud_sno;use ud_sno;create table S(Sno char(6) primary key,Sname char(10) not null unique,Ssex char(6) not null check(Ssex in ('male','female')),Sage smallint check(Sage>16),Sdept char(8) default 'JSJ' #http://www.w3school.com.cn/sql/sql_default.asp);create t 阅读全文