0

如何更新子类型的列值?

像这样的代码无法访问学生的成绩属性:

update persons set grade = 'graduated';
CREATE OR REPLACE TYPE person (
    name varchar2(20),
    age number,
    address varchar2(20)
) NOT FINAL;

CREATE OR REPLACE TYPE student UNDER person (
    grade varchar2(20)
) NOT FINAL;

CREATE TABLE persons OF person;

INSERT INTO persons VALUES (student('Jon', 'undergraduate'));

如何将学生成绩更改为“已毕业”?

4

2 回答 2

1

我找到了我的问题的答案。
这是更新子类型属性的代码:

DECLARE
    s student;

BEGIN
    select treat(value(p) as student) into s from persons p where name = 'Jon';
    s.grade = 'graduated';
    update persons p set value(p) = s where name = 'Jon';
END;
于 2019-05-27T13:55:17.463 回答
0

那应该工作

update persons s set VALUE(s) = student(treat(value(s) as student).name, 'graduated');
于 2019-05-27T13:20:42.243 回答