一个小型数据库 DBMS

create table student ( name char(10) num int ); create table class1 ( classroom char(8) classnum int ); create table class2 ( classroom char(9) classnum int ); E:\\MyProjects\\DBMS\\date\\zhiduan.dat insert into class2 ( classroom classnum ) value ( 'aaaa' , 20 ); insert into class2 ( classroom classnum ) value ( 'aaab' , 20 ); insert into class2 ( classroom classnum ) value ( 'aaac' , 20 ); insert into class2 ( classroom classnum ) value ( 'aaad' , 20 ); insert into student ( name num ) value ( 'yssa' , 10 ); insert into student ( name num ) value ( 'yssb' , 40 ); insert into student ( name num ) value ( 'yjec' , 90 ); insert into student ( name ,num ) value ( 'ysss' , 10 ); insert into student ( name ,num ) value ( 'ysss' , 40 ); insert into student ( name ,num ) value ( 'yjee' , 90 ); insert into class1 ( classroom ,classnum ) value ( 'bbba' , 30 ); insert into class1 ( classroom ,classnum ) value ( 'cccb' , 30 ); insert into class1 ( classroom ,classnum ) value ( 'bbbc' , 30 ); insert into class1 ( classroom ,classnum ) value ( 'bbbd' , 30 ); insert into class1 ( classroom ,classnum ) value ( 'bbbe' , 30 ); insert into class1 ( classroom ,classnum ) value ( 'cccf' , 30 ); insert into class1 ( classroom ,classnum ) value ( 'bbbg' , 30 ); insert into class1 ( classroom ,classnum ) value ( 'bbbh' , 30 ); insert into class1 ( classroom ,classnum ) value ( 'bbbh' , 40 ); insert into class2 ( classroom ,classnum ) value ( 'aaaa' , 20 ); insert into class2 ( classroom ,classnum ) value ( 'aaab' , 20 ); insert into class2 ( classroom ,classnum ) value ( 'aaac' , 20 ); insert into class2 ( classroom ,classnum ) value ( 'aaad' , 20 ); insert into class2 ( classroom ,classnum ) value ( 'aaad' , 30 ); insert into class2 ( class ,classnum ) value ( 'aaaa' , 20 ); create table room ( id int name char(10) num int class char(10) ); insert into room ( id ,name , num ,class ) value ( 1 , 'no1' , 20 , 'liuz' ) ; update class1 set classnum=50 where classroom='bbba' ; insert into student ( name num ) value ( 'ysss' , 21 ); select name,num from student where name='刘朋' ; select name,num from student where 1 ; select classroom,classnum from class2 where 1 ; select classroom,classnum from class2 student where name='刘朋' and num=20 ; select name,num from class2,student where name='刘朋' and num=20 ; select name,num from student,class2 where name='刘朋 and num=20 ; select classroom,classnum from class1 where 1 ; select name,num from student,class2 where name='aaaa' and num=20 ; select name,num from student where name='ysss' and num=10 ; select * from student where 1 ; delete from student where num>=10 ; delete from student where name='aa' and num=20 ; delete from student where num>30 ; delete from student where name='yjee' and num=90 ; delete from student where name='yjee' and num<40; delete from student where num=40; delete from class2 where classnum=20 ; delete from class1 where classnum=30 ; delete from class1 where classroom='bbba' or classnum=40 ; delete from class2 where classnum<30 ;