我想最初学习数据库时都是以student表、course表和sc表为例的吧
首先创建这三张表：必要时可重新创建用户及密码并登陆
环境：oracle 10g
declare
vcnt number;
begin
select count(*) into vcnt from user_tables where table_name='SC';
If vcnt = 1 Then
Execute immediate 'drop table sc';
end if;
select count(*) into vcnt from user_tables where table_name='STUDENT';
If vcnt = 1 Then
Execute immediate 'drop table student';
end if;
select count(*) into vcnt from user_tables where table_name='COURSE';
If vcnt = 1 Then
Execute immediate 'drop table course';
end if;
end;
/
--创建表
Create table student
(sno char(10) primary key,
sname varchar(20) not null,
sage smallint,
ssex char(2),
sdept varchar(20));
Create table course
(cno char(10) primary key,
cname varchar(20) not null,
credit smallint);
Create table sc
(sno char(10),
cno char(10),
grade smallint,
primary key(sno,cno));
--向表中插入数据
insert into student values('001','葛灵','19','f','MA');
insert into student values('002','岳林月','25','f','MA');
insert into student values('003','姬胜俊','16','f','CS');
insert into student values('004','马源','20','f','MA');
insert into student values('005','翁印','23','m','C');
insert into course values('C01','C语言','4');
insert into course values('C02','数学','4');
insert into course values('C03','英语','2');
insert into course values('C04','计算机','5');
insert into course values('C05','数字电路','3');
insert into course values('C06','数据库','2');
--001号学生选修课程
insert into sc values('001','C05','75');
insert into sc values('001','C01','68');
insert into sc values('001','C03','86');
insert into sc values('001','C02','40');
insert into sc values('001','C04','97');
--002号学生选修课程
insert into sc values('002','C01','60');
insert into sc values('002','
在plsql中，面向对象的程序设计是基于对象类型来完成的。对象类型是用户自定义的一种复合数据类型，它封装了数据结构和用于操纵这些数据结构的过程和函数，在建立复杂应用程序时，通过使用对象类型可以降低应用开发难度，进而提高应用开发的效率和速度。
对象类型包括对象类型规范（object type specification）和对象类型 ......
