创建并使用50q数据库

--创建并使用数据库------------*/
create database 50q;
use 50q;
/*-------------------建表-------------------------*/
 CREATE TABLE STUDENT 
(   SNO       VARCHAR(3) NOT NULL,   
 SNAME     VARCHAR(4) NOT NULL, 
 SSEX      VARCHAR(2) NOT NULL,  
 SBIRTHDAY DATETIME, 
 CLASS     VARCHAR(5) 
 );
 CREATE TABLE COURSE 
(  
 CNO   VARCHAR(5)  NOT NULL,  
 CNAME VARCHAR(10) NOT NULL, 
 TNO   VARCHAR(3) NOT NULL 
 );
 CREATE TABLE SCORE   
(  
 SNO    VARCHAR(3)     NOT NULL,  
 CNO    VARCHAR(5)     NOT NULL,  
 DEGREE NUMERIC(10, 1) NOT NULL  
 ) ; 
  CREATE TABLE TEACHER   
(  
 TNO       VARCHAR(3)  NOT NULL,   
 TNAME     VARCHAR(4)  NOT NULL,   
 TSEX      VARCHAR(2)  NOT NULL,   
 TBIRTHDAY DATETIME    NOT NULL,   
 PROF      VARCHAR(6),   
 DEPART    VARCHAR(10) NOT NULL  
 );
/*---------------添加主键--------------*/
  ALTER TABLE STUDENT ADD PRIMARY KEY (SNO); 
 ALTER TABLE SCORE   ADD PRIMARY KEY (SNO,CNO);  
 ALTER TABLE COURSE  ADD PRIMARY KEY (CNO);  
 ALTER TABLE TEACHER ADD PRIMARY