oracle - 如何使用oracle从存储的函数中检索多行

Question

我正在尝试在 oracle 中创建一个返回多行的存储函数。

我的问题与 this one 非常相似除了我想获取一个 select *询问

简而言之，我想创建一个返回此查询结果的函数

select * from t_email_queue

我试过的是这样的:

create or replace
PACKAGE email_queue AS 

  type t_email_queue_type is table of T_EMAIL_QUEUE%ROWTYPE;  

  FUNCTION lock_and_get return t_email_queue_type;

END email_queue;

create or replace
PACKAGE BODY email_queue AS 

    FUNCTION lock_and_get RETURN t_email_queue_type AS 
      queue_obj t_email_queue_type;

      cursor c (lockid in varchar2) is select * from t_email_queue where lockedby = lockid;
      lockid varchar2(100) := 'alf';
    BEGIN

      OPEN c(lockid);
      FETCH c bulk collect INTO queue_obj;

      return queue_obj;

    END lock_and_get;

END email_queue;

该包编译得很好但是当我尝试使用此查询调用它时

select * from table(email_queue.lock_and_get);

oracle抛出以下错误

ORA-00902: invalid datatype
00902. 00000 -  "invalid datatype"
*Cause:    
*Action:
Error at Line: 1 Column: 20

我认为 Oracle 希望我在架构级别创建我的返回类型，但是当我尝试这样做时

create type t_email_queue_type is table of T_EMAIL_QUEUE%ROWTYPE;  

甲骨文提示

Type IMAIL.T_EMAIL_QUEUE_TYPE@imail dev
Error(1): PL/SQL: Compilation unit analysis terminated
Error(2,37): PLS-00329: schema-level type has illegal reference to IMAIL.T_EMAIL_QUEUE

有人可以指出我正确的方向吗？我在这里缺少什么？

谢谢阅读!

Answer 1

对于 SQL 类型，您不能执行 %ROWTYPE，您必须键入每一列以匹配表 *。

*sys.anydataset 放在一边。但沿着这条路走下去，编码要复杂得多。

例如如果你的 table 是

create table foo (id number, cola varchar2(1));

然后

create type email_queue_type is object (id number, cola varchar2(1));
/
create type t_email_queue_type as table of email_queue_type;
/

并使用该表 email_queue_type_tab 作为函数的输出。

但我建议使用流水线函数，因为您当前的代码不可扩展。

例如:

SQL> create table foo (id number, cola varchar2(1));

Table created.

SQL>
SQL> create type email_queue_type is object (id number, cola varchar2(1));
  2  /

Type created.

SQL> create type t_email_queue_type as table of email_queue_type;
  2  /

Type created.

SQL> insert into foo select rownum, 'a' from dual connect by level <= 10;

10 rows created.

SQL>
SQL> create or replace PACKAGE email_queue AS
  2
  3
  4    FUNCTION lock_and_get return t_email_queue_type pipelined;
  5
  6  END email_queue;
  7  /

Package created.

SQL> create or replace PACKAGE BODY email_queue AS
  2
  3      FUNCTION lock_and_get RETURN t_email_queue_type pipelined AS
  4        queue_obj t_email_queue_type;
  5
  6      BEGIN
  7
  8       for r_row in (select * from foo)
  9              loop
 10                pipe row(email_queue_type(r_row.id, r_row.cola));
 11              end loop;
 12
 13      END lock_and_get;
 14
 15  END email_queue;
 16  /

Package body created.

SQL> select * from table(email_queue.lock_and_get());

        ID C
---------- -
         1 a
         2 a
         3 a
         4 a
         5 a
         6 a
         7 a
         8 a
         9 a
        10 a

10 rows selected.

SQL>