『ORACLE』 约束实验（11g）
时间：2021-07-01 10:21:17
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( sno NUMBER(5) not null, sname VARCHAR2(20), idcard VARCHAR2(18), createtime DATE default SYSDATE, nno NUMBER(2), constraint PK_STUDENT primary key (sno));create table course ( cno NUMBER(5) not null, cname VARCHAR2(20), constraint PK_COURSE primary key (cno));create table nativeplace ( nno NUMBER(2) not null, np_name VARCHAR2(20), constraint PK_NATIVEPLACE primary key (nno));create table sc ( sno NUMBER(5) not null, cno NUMBER(5) not null, grade NUMBER(4,1), constraint PK_SC primary key (sno, cno));alter table sc add constraint fk_sc_sno foreign key (sno) references student (sno) on delete cascade;alter table sc add constraint fk_sc_cno foreign key (cno) references course (cno);alter table student add constraint fk_student foreign key (nno) references nativeplace (nno) on delete set null;insert into nativeplace values(1,‘heilongjiang‘);insert into nativeplace values(2,‘jilin‘);insert into nativeplace values(3,‘liaoning‘);insert into nativeplace values(4,‘beijing‘);insert into course VALUES(1,‘Oracle‘);insert into course VALUES(2,‘Java‘);insert into course VALUES(3,‘C++‘);insert into student values(1,‘zhangsan‘,‘123456789123456780‘,default,1);insert into student values(2,‘lisi‘,‘123456789123456781‘,default,2);insert into student values(3,‘wangwu‘,‘123456789123456782‘,default,3);insert into student values(4,‘zhaoliu‘,‘123456789123456783‘,default,4);insert into sc values(1,1,91);insert into sc values(1,2,92);insert into sc values(1,3,93);insert into sc values(2,1,88);insert into sc values(2,2,77);insert into sc values(2,3,99);insert into sc values(3,1,65);insert into sc values(3,2,75);insert into sc values(3,3,85);insert into sc values(4,1,80);insert into sc values(4,2,88);insert into sc values(4,3,89);commit;alter table sc drop constraint fk_sc_sno;alter table sc drop constraint fk_sc_cno;alter table student drop constraint fk_student;drop table course cascade constraints;drop table nativeplace cascade constraints;drop table sc cascade constraints;drop table student cascade constraints;『ORACLE』 约束实验（11g）
标签：number set span native course efault sysdate varchar2 constrain
