Oracle SYS_REFCURSOR不能用作返回类型 [英] Oracle SYS_REFCURSOR couldn't use as a return type

问题描述

我需要使用oracle 11g中的成员函数提取并显示db中所有记录的所有年份.

I need to extract and display all the years for all the records in db using member function in oracle 11g.

CREATE or replace TYPE BODY student_t AS 
MEMBER FUNCTION getYear RETURN SYS_REFCURSOR IS
yearDOB SYS_REFCURSOR;
BEGIN
    for c in (SELECT EXTRACT(YEAR FROM s.dob) c_year from student s)
    loop
        yearDOB := c.c_year; 
    end loop;
    return yearDOB; 
END;END;/

由于我需要为提取函数返回多个值，因此我声明了SYS_REFCURSOR类型的变量以返回.但这会产生以下错误.

Since I need to return multiple values for the extract function I have declared a SYS_REFCURSOR type variable to return. But it will generate following errors.

7/1      PL/SQL: Statement ignored,
7/14     PLS-00382: expression is of wrong type

更改为以下答案后的输出.

output after changed as following answer.

光标声明:1

光标声明:1

  1993
  1995

光标声明:1

光标声明:1

  1993
  1995

学生类型如下.

create type student_t as object(
stno char(4),
dob date)/ 
alter type student_t add member function getYear RETURN SYS_REFCURSOR cascade;/

推荐答案

我不确定您要实现的目标，但我认为您误解了oracle中的对象概念. 在我的示例中，我假设
1)使用此脚本create table student of student_t;

I'm not sure what you are trying to achieve but I think you misunderstood concept of object in oracle. In my example i'm assuming
1) Table studens is create with this script create table student of student_t;

drop table student;

创建类型规范和正文.

Create type spec and body.

create or replace type student_t as object(
stno char(4),
dob date,
member function getYear return number

)
;

create or replace type body student_t as

    member function getYear return number is 
    begin 
            return  EXTRACT(YEAR FROM self.dob);
    end;

end;

创建studnet表

create table student of student_t;

填充表格

declare 
  v_student student_t;
begin 
for i in 0 .. 10 loop 
  insert into student values(student_t('ST'||+mod(i,3),to_date('01-01-'||to_char(2000+i),'dd-mm-yyyy')));
end loop;
commit;
end; 

查询.

select s.*,s.getYear() from student s;

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